Be ready at any time: postprandial synthesis of salivary proteins in salivary gland cells of the haematophagous leech Hirudo verbana

Abstract

Sanguivorous leeches are ectoparasites having access to body fluids of potential hosts only infrequently. During feeding, salivary proteins are released from unicellular salivary glands into the wound. These substances, among them anti-coagulants, anti-inflammatory or antimicrobial agents, allow these animals proper feeding and long-term storage of host blood in their crops for several months. Using histological, protein biochemical and molecular techniques, we investigated whether synthesis of salivary proteins and refilling of salivary gland cells occur immediately after feeding or later when stored nutrients in the crop are getting scarce. The results of the histological analyses showed that gland cell area was significantly smaller right after feeding when compared with those in unfed animals. This parameter recovered quickly and reached the control level at 1 week after feeding. 2D gel electrophoresis and analysis of the abundance of individual proteins in extracts of leech tissues revealed that a subset of proteins that had been present in extracts of unfed animals virtually disappeared during feeding, but re-appeared within 1 week of feeding (most probably secretory proteins) while another subset did not change during the experimental period (most probably housekeeping proteins). Semi-quantitative PCR analysis of hirudin cDNA prepared from leech RNA samples revealed that the amount of hirudin transcripts increased immediately after feeding, peaked at 5 days after feeding and declined to control values thereafter. Our results indicate that bloodsucking leeches synthesize salivary proteins and refill their salivary gland cell reservoirs within a week of a blood meal to be prepared for another feeding opportunity.

Identification and characterization of hirudin-HN, a new thrombin inhibitor, from the salivary glands ofHirudo nipponia

“…Most of these studies used leeches that had been starved for a certain period of time (Scacheri et al, 1993). Lemke, Müller & Hildebrandt (2016) reported that feeding-associated salivary protein content was reduced when Hirudo verbena started feeding until the fifth day after feeding. For the hirudin-HN in our study, the protein content of FG was lower than that of the other two groups (UFG and FIG), which was consistent with the trend in Lemke, Müller & Hildebrandt’s (2016) research.…”

“…Lemke, Müller & Hildebrandt (2016) reported that feeding-associated salivary protein content was reduced when Hirudo verbena started feeding until the fifth day after feeding. For the hirudin-HN in our study, the protein content of FG was lower than that of the other two groups (UFG and FIG), which was consistent with the trend in Lemke, Müller & Hildebrandt’s (2016) research. In addition, similar to the activity in the blood-sucking leech P. manillensis , the anticoagulant activity was higher in the head than in other parts of the body (Gou et al, 2016).…”

Draft genome sequences of Hirudo medicinalis and salivary transcriptome of three closely related medicinal leeches

“…During one act of blood meal, medicinal leeches partially or completely empty their salivary gland cells [11]. Salivary gland cells have been shown to replenish their reservoirs with the content of SCS within 7 days after blood meal [12]. In addition to its known inhibitory effect on haemostasis and blood coagulation, SCS suppresses inflammation, exhibits analgesic effects, possesses antimicrobial activity, and alters vasodilatory responses, enhancing local blood circulation to facilitate leech feeding.…”

European Medicinal Leeches—New Roles in Modern Medicine

“…Some leech-specific anticoagulants were also found in leeches that do not feed on blood, such as Whitmania pigra [62]. Interestingly, these anticoagulants were upregulated after feeding [62] just as they are in blood-feeding leeches [63].…”