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  • Author or Editor: A. Szél x
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Cerebrospinal fluid (CSF)-contacting neurons are sensory-type cells sending ciliated dendritic process into the CSF. Some of the prosencephalic CSF-contacting neurons of higher vertebrates were postulated to be chemoreceptors detecting the chemical composition of the CSF, other cells may percieve light as „deep encephalic photoreceptors". In our earlier works, CSF-contacting neurons of the mechanoreceptor-type were described around the central canal of the hagfish spinal cord. It was supposed that perceieving the flow of the CSF they are involved in vasoregulatory mechanisms of the nervous tissue. In the present work, we examined the brain ventricular system of the Atlantic hagfish with special reference to the presence and fine structure of CSF-contacting neurons. Myxinoids have an ontogenetically reduced brain ventricular system. In the adult hagfish (Myxine glutinosa) the lumen of the lateral ventricle is closed, the third ventricle has a preoptic-, infundibular and subhabenular part that are not connected to each other. The choroid plexus is absent. The infundibular part of the third ventricle has a medial hypophyseal recess and, more caudally, a paired lateral recess. We found CSF-contacting neurons in the lower part of the third ventricle, in the preoptic and infundibular recess as well as in the lateral infundibular recesses. No CSF-contacting neurons were found in the cerebral aqueduct connecting the subhabenular recess to the fourth ventricle. There is a pineal recess and a well-developed subcommissural organ at the rostral end of the aqueduct. Extending from the caudal part of the fourth ventricle in the medulla to the caudal end of the spinal cord, the central canal has a dorsal and ventral part. Dendrites of CSF-contacting neurons are protruding into the ventral lumen. Corroborating the supposed choroid plexus-like function of the wall of the dorsal central canal, segmental vessels reach a thin area on both sides of the ependymal lining. The perikarya of the CSF-contacting neurons found in the brain ventricles are mainly bipolar and contain granular vesicles of various size. The bulb-like terminal of their ventricular dendrites bears several stereocilia and contains basal bodies as well as mitochondria. Basal bodies emit cilia of the 9+0-type. Cilia may arise from the basal body and acessory basal body as well. The axons run ependymofugally and enter - partially cross - the periventricular synaptic zones. No neurohemal terminals similar to those formed by spinal CSF-contacting neurons of higher vertebrates have been found in the hagfish. We suppose that CSF-contacting neurons transform CSF-mediated non-synaptic information taken up by their ventricular dendrites to synaptic one. A light-sensitive role for some (preoptic) groups of CSF-contacting neurons cannot be excluded.

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Sugar composition, pH, invertase and diastase activity and colour of 7 robinia (Robinia pseudoacacia) and 8 milkweed (Asclepias syriaca) honey samples were compared, all purchased from producers and wholesalers. Milkweed honeys proved to be of darker colour and more acidic. The two unifloral honeys showed statistically significant differences between their diastase and invertase activities, milkweed honey showed higher enzyme activity values than robinia honey. The fructose to glucose ratio was 1.58 in case of robinia honey and 1.28 in case of milkweed honey. There was also a significant difference between the di- and trisaccharide content of the two unifloral honeys.

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The aim of the study was the identification and characterisation of coagulase-positive Staphylococcus bacteria obtained from food matrices by mass spectrometry and molecular methods. A total of 46 coagulase-positive Staphylococcus isolates were collected from different foodstuffs. The Staphylococcus isolates were identified by MALDI-TOF MS and confirmed by the presence and sequence analysis of the Staphylococcus protein A gene. Staphylococcal enterotoxin genes were also investigated by multiplex PCR. Based on the identification of strains by the MALDI-TOF MS technique and spa-typing, all strains were identified as Staphylococcus aureus. Based on their MS peak profiles, the isolates matched the spectra of three S. aureus reference strains in the Bruker MALDI Biotyper database, with identification scores higher than 1.999 in the case of all 46 (100%) isolates. The isolates showed great genetic variability. Twenty spa types were identified, from which most lineages are capable of colonizing humans. Fifty percent of the strains harboured at least one of four enterotoxin genes (seg, seh, sei, and ser), but none of the classical enterotoxin genes could be detected.

Open access
Acta Alimentaria
Authors:
Zs. Szél
,
Á. Kardos-Neumann
,
P. Á. Biacs
,
E. Szalai-Mátray
, and
A. Takáts

Diastase and glucose-oxidase activity was determined in 8 samples of Hungarian milkweed (Asclepias syriaca) honey and in 10 samples of Hungarian acacia (Robinia pseudoacacia) honey. The aim of the study was to compare diastase and glucose-oxidase activity of milkweed and acacia honey. Mean value for diastase was 16.28 diastase number (DN) (±2.53) in acacia honey and 24.48 DN (±5.07) in milkweed honey. Mean value for glucose-oxidase was 3.67 nmol unit g–1 (±3.31) in acacia honey and 8.24 (±4.21) in milkweed honey. The differences both in diastase and glucose-oxidase activities of the two honey types were statistically significant.

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In earlier works we have found that in the mammalian pineal organ, a part of autonomic nerves - generally thought to mediate light information from the retina - form vasomotor endings on smooth muscle cells of vessels. We supposed that they serve the vascular support for circadian and circannual periodic changes in the metabolic activity of the pineal tissue. In the present work, we investigated whether peripheral nerves present in the photoreceptive pineal organs of submammalians form similar terminals on microvessels. In the cyclostome, fish, amphibian, reptile and bird species investigated, autonomic nerves accompany vessels entering the arachnoidal capsule and interfollicular meningeal septa of the pineal organ. The autonomic nerves do not enter the pineal tissue proper but remain in the perivasal meningeal septa isolated by basal lamina. They are composed of unmyelinated and myelinated fibers and form terminals around arterioles, veins and capillaries. The terminals contain synaptic and granular vesicles. Comparing various vertebrates, more perivasal terminals were found in reptiles and birds than in the cyclostome, fish and amphibian pineal organs. Earlier, autonomic nerves of the pineal organs were predominantly investigated in connection with the innervation of pineal tissue. The perivasal terminals found in various submammalians show that a part of the pineal autonomic fibers are vasomotoric in nature, but the vasosensor function of some fibers cannot be excluded. We suppose that the vasomotor regulation of the pineal microvessels in the photosensory submamalian pineal - like in mammals - may serve the vascular support for circadian and circannual periodic changes in the metabolic activity of the pineal tissue. The higher number of perivasal terminals in reptiles and birds may correspond to the higher metabolic activity of the tissues in more differentiated species.

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