Dietary amino acid and vitamin complex protects honey bee from immunosuppression caused by Nosema ceranae.

Microsporidium Nosema ceranae is well known for exerting a negative impact on honey bee health, including down-regulation of immunoregulatory genes. Protein nutrition has been proven to have beneficial effects on bee immunity and other aspects of bee health. Bearing this in mind, the aim of our study was to evaluate the potential of a dietary amino acid and vitamin complex "BEEWELL AminoPlus" to protect honey bees from immunosuppression induced by N. ceranae. In a laboratory experiment bees were infected with N. ceranae and treated with supplement on first, third, sixth and ninth day after emergence. The expression of genes for immune-related peptides (abaecin, apidaecin, hymenoptaecin, defensin and vitellogenin) was compared between groups. The results revealed significantly lower (p<0.01 or p<0.001) numbers of Nosema spores in supplemented groups than in the control especially on day 12 post infection. With the exception of abacein, the expression levels of immune-related peptides were significantly suppressed (p<0.01 or p<0.001) in control group on the 12th day post infection, compared to bees that received the supplement. It was supposed that N. ceranae had a negative impact on bee immunity and that the tested amino acid and vitamin complex modified the expression of immune-related genes in honey bees compromised by infection, suggesting immune-stimulation that reflects in the increase in resistance to diseases and reduced bee mortality. The supplement exerted best efficacy when applied simultaneously with Nosema infection, which can help us to assume the most suitable period for its application in the hive.

Reflections About Inflammatory Bowel Disease and Vitamins A and D.

Ulcerative colitis and Crohn's disease are two major forms of the inflammatory bowel diseases (IBDs). Vitamin A (VA) and vitamin D (VD) may be associated with reduction in inflammation in these disorders. The aim of this review was to show the current evidence that may associate VA and VD with IBDs. Data linking VA, VD, and IBDs were studied. Both VA and VD may be related to the immune system in different manners. The active form of VA, retinoic acid, may be related to the growth factor-ß and release of interleukin-10 (IL-10), thus involved with the resolution of the inflammation. Its deficiency is associated with the increase of disease activity. The active form of VD is 1,25(OH)2D3 that produces biological effects via the nuclear hormone receptor named VD receptor (VDR), which may interfere with the immune cells and macrophages leading to the suppression of the inflammatory process by decreasing the release of TNF-α, IL-1, IL-6, and IL-8, IL-12, and IL-23. VDR may also activate nucleotide-binding oligomerization domain 2 expression and stimulate the production of the defensin and cathelicidin that are important to the homeostasis of the mucosal immune barrier. The use of VA and VD could be helpful in the treatment and prevention of IBDs but more studies are necessary to establish the precise role of these compounds in the prevention or remission of these inflammatory processes.

Expression of lucifensin in Lucilia sericata medicinal maggots in infected environments.

Lucifensin, a novel larval defensin, is one of the antibacterial agents of medicinal maggots involved in maggot therapy. The goal of this study was to examine lucifensin expression in various larval tissues during Lucilia sericata development and in maggots exposed to a variety of infectious environments in vitro. In situ hybridisation revealed lucifensin expression in the salivary glands of all larval stages. Expression was occasionally detected in a few cells of the fat body and in the grease coupler of the salivary glands. Expression of lucifensin in the salivary glands was initiated 5-6 h after hatching from the egg. Maximum expression was reached about 24 h after hatching, remained strong during the second and third instars and declined at the end of the third instar, before the wandering stage. Expression of lucifensin was also investigated in maggots after oral ingestion of certain pathogens regularly found in infected chronic wounds. No differences were detected in the salivary glands after stimulation by wound bacterial isolates. However, lucifensin expression was strongly stimulated in the fat body by the presence of Staphylococcus aureus and Pseudomonas aeruginosa. Our data suggest that certain infectious environments increase lucifensin expression only in the fat body, whereas its production and antimicrobial activity in excretion/secretion products are not affected.

Vitamin D and respiratory infection in adults.

Vitamin D insufficiency is a global issue that has significant implications for health. The classical role of vitamin D in bone mineralisation is well known; vitamin D deficiency leads to rickets, osteomalacia or osteoporosis. The role of vitamin D in an immune system is less known. Vitamin D is not an actual vitamin but a secosteroid hormone produced in the skin from 7-dehydrocholesterol after exposure to sunlight UVB radiation. Nutrition and supplements are main sources of vitamin D in wintertime in northern countries as sunlight exposure is inadequate for the production. For activation vitamin D needs to be hydroxylated in liver to form 25-hydroxyvitamin D and in kidney to 1,25-dihydroxyvitamin D, the most active hormone in Ca absorption in the gut. For determination of vitamin D status serum 25-hydroxyvitamin D level, the major circulating form of the hormone is to be measured. Vitamin D regulates gene expression through binding with vitamin D receptors, which dimerises with retinoid X receptor. This complex binds to vitamin D-responsive elements inside the promoter regions of vitamin D-responsive genes. Vitamin D has a key role in innate immunity activation; the production of antimicrobial peptides (cathelicidin and defensins) following Toll-like receptor stimulation by pathogen lipopeptides is dependent on sufficient level of 25-hydroxyvitamin D. Clinically, there is evidence of the association of vitamin D insufficiency and respiratory tract infections. There is also some evidence of the prevention of infections by vitamin D supplementation. Randomised controlled trials are warranted to explore this preventive effect.

Expression and functional characterization of the plant antimicrobial snakin-1 and defensin recombinant proteins.

In this study, for the first time, functionally active, recombinant, cysteine-rich plant proteins snakin-1 (SN1) and defensin (PTH1) were expressed and purified using a prokaryotic expression system. The overall level of antimicrobial activities of SN1 and PTH1 produced in Escherichia coli was commensurate with that of the same proteins previously obtained from plant tissues. Both proteins exhibited strong antibacterial activity against the phytopathogenic bacterium Clavibacter michiganensis subsp. sepedonicus (50% inhibitory concentration (IC(50)) 1.5-8 microM) and antifungal activity against the phytopathogenic fungi Colletotrichum coccoides and Botrytis cinerea (IC(50) 5-14 microM). Significantly weaker activity was observed against Pseudomonas syringae pv. syringae and Pseudomonas syringae pv. tabaci. A pronounced synergistic antimicrobial effect against P. syringae pv. syringae and an additive effect against P. syringae pv. tabaci occurred with a combination of SN1 and PTH1. Aggregation of C. michiganensis subsp. sepedonicus bacterial cells at all protein concentrations tested was observed with the combination of SN1 and PTH1 and with SN1 alone. Our results demonstrate the use of a cost effective prokaryotic expression system for generation and in vitro characterization of plant cysteine-rich proteins with potential antimicrobial activities against a wide range of phytopathogenic microorganisms in order to select the most effective agents for future in vivo studies.

Assessment of the cellular response to the induced expression of defensin sense and antisense cDNA in acute promyelocytic leukemia cell lines.

Defensins are 20-30 amino acid-long, cystine- and arginine-rich peptides that constitute more than 5% of the total cellular proteins in mature granulocytes and at least 30% of proteins in primary granules. Human defensins were reported to have antimicrobial, antifungal, antiviral and tumor lysis activities. Defensin mRNA was isolated using the differential display technique from the well-characterized all-trans retinoic acid (ATRA)-responsive acute promyelocytic leukemia cell line, NB4. The differential display analysis showed an up-regulation of defensin mRNA in NB4 cells after treatment with 10(-7) M ATRA for 24 h. This expression was not seen in an NB4:R2 cell line, an ATRA-resistant subclone of NB4 cells. In order to investigate further the effects of this gene on our cellular model, we virally infected our cells with full-length defensin cDNA in the sense and antisense directions. Sense defensin induced cell growth arrest and cell death in both cell lines. While NB4 cells died within 48-73 h, NB4:R2 cells survived for 96 h before dying in culture. Phenotypic analysis showed high expression of Annexin V in sense-infected cells compared with antisense and uninfected cells in both cell lines. There was not a significant increase in CD11b expression in any of the 2 cell lines used. No cellular response was encountered in antisense-infected cells. Our data suggest that defensin is not only a reliable marker for granulocytic differentiation, but can also be considered a candidate target for molecular therapy in acute promyelocytic leukemia.