Seasonal trends of the ABPV, KBV, and IAPV complex in Italian managed honey bee (Apis mellifera L.) colonies

Acute bee paralysis virus (ABPV), Kashmir bee virus (KBV), and Israeli acute paralysis virus (IAPV) usually persist as covert infections in honey bee colonies. They can cause rapid bee mortality in cases of severe infection, often associated with high Varroa destructor infestation, by which they are transmitted. In various countries, these viruses have been associated with colony collapse. Despite their potential danger, these viruses are often disregarded, and little information is available on their occurrence in many countries, including Italy. In 2021, 370 apiaries representing all of the Italian regions were investigated in four different months (June, September, November, and March) for the presence of ABPV, KBV, and IAPV. IAPV was not found in any of the apiaries investigated, whereas 16.45% and 0.67% of the samples tested positive for ABPV and KBV, respectively. Most ABPV cases occurred in late summer-autumn in both northern and southern regions. We observed a scattered pattern of KBV-positive colonies that did not allow any seasonal or regional trends to be discerned. Differences observed among regions and months were potentially related to the dynamics of varroa infestation, viral genetic variations, and different climatic conditions resulting in variations in bee behaviour. This study improves our understanding of the circulation of bee viruses and will contribute to better disease prevention and preservation of bee health.

Floral origin modulates the content of a lipid marker in Apis mellifera honey

The compound DAGE (DiAcyl Glyceryl Ether, 1-stearyl-2,3-dioleoyl glycerol), present in Apis mellifera honey, is a lipidic entomological marker secreted by the salivary glands of worker bees. Its content was determined by NMR, analyzing the organic extracts of a number of Italian honeys of different floral typology. We have found that the DAGE content is related to the botanical origin of honey. This dependence on floral typology was further confirmed by a linear correlation (R² > 0.83) observed between the content of DAGE and the enzymatic activity of invertase and diastase in honey. Also these enzymes originate from bee salivary secretions and their concentrations in honey are known to depend on the floral source. DAGE content appears to be a sensitive parameter to some forms of honey manipulations, as indicated by the results of artificial bee-feeding experiments. This suggests its possible use as indicator of honey authenticity.

Investigation of water state during induced crystallization of honey

This work studied water state of honey during crystallization, obtained statically and dynamically, by differential scanning calorimetry (DSC), water activity (a_w) assessment and time domain nuclear magnetic resonance (TD-NMR). Crystallization was induced by adding 5% of crystallized honey to three honey samples with different fructose/glucose ratio, the key characteristic for honey crystallization. Samples were stored at 14 °C. Dynamic crystallization was obtained by using an impeller. DSC showed that the dynamic crystallization was faster than the static one, the latter characterized by two phases, showing different rates. The crystallization rate did not affect a_w, that remained below 0.600. TD-NMR allowed to separately observe two kinds of protons, both pertaining to liquid sugars, one chemically exchanging with water and one not exchanging with it. The combination of techniques allowed speculating that the two crystallization methods led to crystals of different size and shape.

Short Communication

Gluten Exorphins are opioid peptides identified in enzymatic digests of gluten. The effects of Gluten Exorphins are still largely unknown. It has been shown that Gluten Exorphin B5 (Tyr-Gly-Gly-Trp-Leu) stimulates Prolactin secretion in male rats. In this study, we have evaluated the Prolactin response to Gluten Exorphin B4, another exorphin whose structure (Tyr-Gly-Gly-Trp) is identical to that of the NH(2)-terminal sequence of Gluten Exorphin B5. To this aim, five groups of male rats were given the following intravenous treatments: vehicle, Gluten Exorphin B5 3 mg kg-1 body weight, Gluten Exorphin B4 at the doses of 3, 6 and 9 mg kg-1 body weight. At the dose of 3 mg kg-1 body weight, Gluten Exorphin B5 induced a significant increase in Prolactin levels. Gluten Exorphin B4 could not modify Prolactin secretion, even when administered at doses three times higher than those effective for Gluten Exorphin B5. The present study: (1) indicates that Gluten Exorphin B4 does not modify Prolactin secretion in male rats; (2) confirms the ability of Gluten Exorphin B5 to exert a stimulatory action on Prolactin release; (3) suggests that the presence of the carboxy-terminal leucine in Gluten Exorphin B5 is essential for its action on Prolactin secretion.

Identification of differentially expressed genes in shrimp ( Penaeus stylirostris ) infected with White spot syndrome virus by cDNA microarrays

White spot syndrome virus (WSSV) is currently the most important viral pathogen infecting penaeid shrimp worldwide. Although considerable progress has been made in characterizing the WSSV genome and developing detection methods, information pertaining to host genes involved in WSSV pathogenesis is limited. We examined the potential of cDNA microarray analysis to study gene expression in WSSV-infected shrimp. Shrimp cDNAs were printed as low-density arrays on glass slides and were hybridized with Cy3/Cy5 labeled probes derived from RNA isolated from healthy and WSSV-infected shrimp. Genes that code for proteins that are relevant to crustacean immunity, structural proteins, as well as proteins of unknown function were among those whose mRNA expression was altered upon WSSV infection. To validate the microarray data, the temporal expression of three differentially expressed genes, an immune gene (C-type lectin-1), a structural gene (40S ribosomal protein), and a gene involved in lipid metabolism (fatty acid binding protein) was measured in healthy and WSSV-infected shrimp by real-time RT-PCR. The data suggest that WSSV infection alters the expression of a wide array of cellular genes, and provides a framework for further studies aimed at identifying genes whose function may provide insight into the mechanism of WSSV infection in shrimp.

Pulsatile gonadotrophin secretion in hypothyroid women of reproductive age

Hypothyroid women may have various disturbances of the reproductive system. Although menstrual cycle disturbances and infertility have been reported in hypothyroidism, gonadotrophin levels have usually been found in the normal range. We have investigated whether female hypothyroid patients of reproductive age have any alteration in the pulsatile secretory pattern of gonadotrophin secretion. LH and FSH were assayed on days 2-5 of the menstrual cycle in blood samples taken every 10 min for 8 h from six hypothyroid women and six age-matched control subjects. Pulsatility was analysed using the Cluster and Detect programs. There was no significant difference in the number of peaks identified (3.7 +/- 0.8 vs 3.7 +/- 0.8 for LH, and 3.7 +/- 0.8 vs 4.2 +/- 0.5 for ESH), the mean duration of peaks (LH: 68.0 +/- 6.9 vs 72.7 +/- 5.1 min; FSH: 81.9 +/- 8.1 vs 71.2 +/- 10.3 min), the area under the peaks (LH: 91.5 +/- 20.4 vs 148.2 +/- 55.1 IU/l per min; FSH: 71.5 +/- 4.5 vs 62.7 +/- 15.0 IU/l per min), and the incremental amplitude from baseline (LH: 2.2 +/- 0.4 vs 3.0 +/- 0.8 IU/l; FSH: 1.4 +/- 0.2 vs 2.1 +/- 0.5 IU/ l). However, the absolute pulse amplitude was greater in hypothyroid patients (LH: 14.5 +/- 1.4 vs 8.3 +/- 1.3 IU/l, P < 0.01; FSH: 9.0 +/- 1.5 vs 5.8 +/- 1.2 IU/l, P = 0.04), as were the integrated concentrations (LH: 6.6 +/- 0.7 vs 3.2 +/- 0.4 IU/l per min, P < 0.01; FSH: 4.3 +/- 0.4 vs 2.1 +/- 0.5 IU/l per min, P < 0.01). Oestradiol values were comparable in the two groups (42.7 +/- 0.4 vs 43.5 +/- 9.7 pg/ml). These results indicate that in hypothyroid women there is an increased baseline level with a normal pulsatility of the gonadotrophin secretion. Similar oestrogen levels in both groups, and normal or near-normal cycles in our patients suggest either a decreased biological potency of the gonadotrophins or a mild ovarian resistance.

L-arginine is unlikely to exert neuroendocrine effects in humans via the generation of nitric oxide

There is now considerable evidence that nitric oxide is an important neuroregulatory agent, but there has been very little investigation of its possible role in neuroendocrine mechanisms in humans. We have investigated the effects of two nitric oxide precursors, L-arginine and molsidomine, under basal conditions on the pituitary hormones growth hormone (GH), prolactin, luteinizing hormone, follicle-stimulating hormone, thyrotrophin, adrenocorticotrophin (ACTH) and vasopressin, and also on serum cortisol; we have also studied the effect of L-arginine on circulating prolactin, ACTH and cortisol in normal human subjects under hypoglycaemic stress. L-Arginine stimulated both GH and prolactin release under basal conditions but had no effect on the other hormones studied, while the nitric oxide donor molsidomine showed no effect on any hormone studied. L-Arginine potentiated the hypoglycaemia-stimulated release of ACTH but did not influence the rise in GH. The current studies suggest that the effects of L-arginine on the stimulation of GH and prolactin release are unlikely to be mediated via the generation of nitric oxide.

Effect of exogenous growth hormone administration on endogenous growth hormone secretion induced by a met-enkephalin analog

Exogenous growth hormone (hGH) administration in humans attenuates the endogenous growth hormone (GH) response to some pharmacological stimuli; in particular, pretreatment with hGH completely blocks the serum GH response to growth hormone-releasing hormone. In order to evaluate the mechanism(s) whereby opiods induce GH secretion in man, we gave the following treatments to six healthy male volunteers: (a) IV saline; (b) a met-enkephalin analog G-DAMME 250 micrograms IV as a bolus at time 0'; (c) hGH 2 IU as an IV bolus at time -180'; (d) G-DAMME as above, preceded by hGH as above. In our study, G-DAMME stimulated GH secretion both basally (peak 17.9 +/- 6.0 ng/ml) and, to a lesser extent, after hGH pretreatment (6.0 +/- 2.7 ng/ml). Since in our study G-DAMME was able to partially overcome the inhibitory effect of hGH administration, it is suggested that opioids act through an inhibition of somatostatin release and not through a GHRH-dependent pathway. However, an additional direct effect of hGH on pituitary somatotrophes cannot be excluded.