The insulin-like peptide (ILP) and insulin-like growth factor (IGF) signalling pathways play a crucial role in the regulation of metabolism, growth and development, fecundity, stress resistance, and lifespan. ILPs are encoded by multigene families that are expressed in nervous and non-nervous organs, including the midgut, salivary glands, and fat body, in a tissue- and stage-specific manner. Thus, more multidirectional and more complex control of insect metabolism can occur. ILPs are not the only factors that regulate metabolism. ILPs interact in many cross-talk interactions of different factors, for example, hormones (peptide and nonpeptide), neurotransmitters and growth factors. These interactions are observed at different levels, and three interactions appear to be the most prominent/significant: (1) coinfluence of ILPs and other factors on the same target cells, (2) influence of ILPs on synthesis/secretion of other factors regulating metabolism, and (3) regulation of activity of cells producing/secreting ILPs by various factors. For example, brain insulin-producing cells co-express sulfakinins (SKs), which are cholecystokinin-like peptides, another key regulator of metabolism, and express receptors for tachykinin-related peptides, the next peptide hormones involved in the control of metabolism. It was also shown that ILPs in Drosophila melanogaster can directly and indirectly regulate AKH. This review presents an overview of the regulatory role of insulin-like peptides in insect metabolism and how these factors interact with other players involved in its regulation.

Insect sulfakinins are pleiotropic neuropeptides with the homology to vertebrate gastrin/cholecystokinin peptide family. They have been identified in many insect species and affect different metabolic processes. They have a strong influence on feeding and digestion as well as on carbohydrate and lipid processing. Our study reveals that sulfakinins influence fatty acids composition in Zophobas atratus oenocytes and regulate insulin-like peptides (ILPs) level in these cells. Oenocytes are cells responsible for maintenance of the body homeostasis and have an important role in the regulation of intermediary metabolism, especially of lipids. To analyze the lipid composition in oenocytes after sulfakinins injections we used gas chromatography combined with mass spectrometry and for ILPs level determination an immunoenzymatic test was used. Because sulfakinin peptides and their receptors are the main components of sulfakinin signaling, we also analyzed the presence of sulfakinin receptor transcript (SKR2) in insect tissues. We have identified for the first time the sulfakinin receptor transcript (SKR2) in insect oenocytes and found its distribution more widespread in the peripheral tissues (gut, fat body and haemolymph) as well as in the nervous and neuro-endocrine systems (brain, ventral nerve cord, corpora cardiaca/corpora allata CC/CA) of Z. atratus larvae. The presence of sulfakinin receptor transcript (SKR2) in oenocytes suggests that observed effects on oenocytes lipid and ILPs content may result from direction action of these peptides on oenocytes.

Human papillomaviruses (HPVs) are a very complex group of pathogenic viruses, with more than 80 types, causing human infection. Given the prevalence of HPV infection and its relationship with the development of cervical and many other cancers, HPV vaccine development has been a major public health initiative worldwide in the last decade. The aim of the presented study was to identify HPV DNA by MY-PCR in 4,150 school children and adolescents, aged 10–18 years in the Wielkopolska region, Poland. All individuals were asked to fill in extensive questionnaires; further normal, oral squamous cells were collected from each pupil. Cellular DNA was isolated and used as a MY-PCR template to estimate the incidence of HPV-active infection. Forty five subjects (1.08% of the sample) were carriers of oropharyngeal HPVs. HPV status and variables of interest, such as age, gender, socioeconomical status, and risk factors (smoking and sexual intercourse history, alcohol consumption) were not correlated. The presence of HPVs in the oral cavity was cumulated in several schools of the region. DNA sequencing of MY-PCR products revealed only four HPV genotypes. The most frequent genotype was HPV11 (38/45 HPV-positive cases), while other more rare genotypes were HPV6 (3/45), HPV12 (3/45), and HPV57 (1/45). Conclusion: Our findings presented herein, reveal a relatively low prevalance of oropharyngeal HPVs in Polish adolescents and fill an important gap in the knowledge of oral HPV infections of children above 10 years and adolescents.