Effect of melittin on mice stomach

Melittin, the main bee venom component, has many positive biological effects and a relatively low toxicity in various cell types. However, there is no evidence of the effect of melittin on gastrointestinal cells. In the present study, we investigated the histological and immuonohistochemical effects of melittin on mice stomach. Adult male mice (Albino Swiss) were randomly divided into two groups (7 mice for each group): control group and melittin only treated group (10 and 40 μg/kg). These mice were sacrificed, then samples from the stomach were collected and prepared for histopathological studies by using alcian blue stain and immuonohistochemical studies by using smooth muscle actin (SMA) antibody. Treatment with melittin alone do not cause any harmful effect on the stomach tissue where the microscopic examination of Alcian blue stained section showed the normal distribution of the mucous secreting cells of the stomach tissues. On other hand, no changes were observed on smooth muscle cells. This study demonstrated the safety of using melittin on gastrointestinal tissues if used in definite dose and for suitable duration, which offers an opportunity for its use as a treatment for many diseases of the gastrointestinal tract.     

Possible gastrointestinal disorders for athletes during Ramadan: an overview

Ramadan is considered to be the month of the stomach break. It has been reported that Ramadan has some health benefits. In most Muslims countries, there is a huge modification in the diet during this month. These changes could induce some gastrointestinal (GI) disorders (e.g. diarrhea, cramps, fullness, nausea). The aims of the present overview were to present some challenges that could be observed for athletes during the training sessions or competition and present some practical recommendations to avoid GI disorders during Ramadan. Based on previous studies, we could advance that the prevalence of GI disorders will be more pronounced when athletes travel for international competitions during Ramadan. Besides, GI disorders are more frequent for athletes when there is a huge modification in the training load. Dehydration observed during Ramadan is one of the factors that may induce GI disorders. The latter could be exacerbated by sweat loss during training sessions. Carbohydrate is frequently used by athletes to improve performance and is associated with some GI disorders. Therefore, during Ramadan, coaches and athletes should be advised to maintain the same diet and a good hydration as before the fasting month, and avoid air travel when preparing for competitions.     

PACAP—A Multifacetted Neuropeptide

Pituitary adenylate cyclase activating polypeptide (PACAP) was originally isolated from ovine hypothalamus based on its ability to stimulate cAMP production in pituitary cell cultures. The peptide exists in two forms, both of which are derived from the same precursor. PACAP38 and the C-terminal truncated PACAP27 can interact with three subtypes of receptors activating adenylate cyclase and/or phospholipase C. Since its discovery, numerous studies have provided evidence that PACAP is a pleiotropic substance having a broad spectrum of biological functions; the peptide can act as a hormone, neurohormone, autocrine/paracrine substance, neurotransmitter, neuromodulator, neurotrophic factor, and immunomodulator. Two examples of the functional role of PACAP on the biological timing system are presented: 1) the transient expression of PACAP during the periovulatory period in ovarian cells, in which PACAP functions as an autocrine/paracrine inducer of progesterone secretion and subsequent luteinization; and 2) the role of PACAP as a neurotransmitter in the retinohypothalamic tract mediating photic regulation of the brain's biological clock.     

Comparative evaluation of the metabolic potentials of different strains of Peptostreptococcus productus: utilization and transformation of aromatic compounds

Three strains of Peptostreptococcus productus were tested for growth at the expense of methoxylated aromatic compounds. Strain M8A-18 (human fecal isolate) was unable to utilize methoxylated aromatic compounds. While the type strain ATCC 27340 (human septicemia isolate) was capable of minimal growth with methoxylated aromatic compounds, ATCC 35244 (sewage sludge isolate) displayed significant growth on methoxylated aromatic compounds. Methoxylated phenols, benzoates, benzyl alcohol and phenylacrylates supported the growth of ATCC 35244 and were O-demethylated to their respective hydroxylated derivatives. During O-methyl- or CO-dependent growth, the double bond of the acrylate side chain of certain methoxylated and non-methoxylated phenylacrylates was reduced. Although other aromatic substituent groups (-COOH and -CH3) were transformed during CO-dependent growth, in short-term growth studies, the aromatic ring was not subject to reduction or degradation. Of the three strains tested, only strain M8A-18 failed to grow at the expense of carbon monoxide (CO).     

Effect of vasoactive intestinal polypeptide on porcine gastrointestinal electrical activity

The influence of intravenous infusion of VIP, 150 and 300 pmol/kg/min, on gastrointestinal electrical activity was studied in conscious piglets with electrodes implanted in the wall of the antrum pylori, duodenum, jejunum, and ileum. Both doses resulted in a decrease in antral electrical activity. In the small intestine, only the lower dose caused a shortening of the irregular spiking activity phase in the jejunum and ileum. In the jejunum this resulted in a reduction of the MMC interval. It may be concluded that the prevailing effect of VIP is an inhibition of gastrointestinal electrical activity in the piglet.