76 research outputs found
Cell-specific synaptic plasticity induced by network oscillations
Gamma rhythms are known to contribute to the process of memory encoding.
However, little is known about the underlying mechanisms at the molecular,
cellular and network levels. Using local field potential recording in awake
behaving mice and concomitant field potential and whole-cell recordings in
slice preparations we found that gamma rhythms lead to activity-dependent
modification of hippocampal networks, including alterations in sharp wave-
ripple complexes. Network plasticity, expressed as long-lasting increases in
sharp wave-associated synaptic currents, exhibits enhanced excitatory synaptic
strength in pyramidal cells that is induced postsynaptically and depends on
metabotropic glutamate receptor-5 activation. In sharp contrast, alteration of
inhibitory synaptic strength is independent of postsynaptic activation and
less pronounced. Further, we found a cell type-specific, directionally biased
synaptic plasticity of two major types of GABAergic cells, parvalbumin- and
cholecystokinin-expressing interneurons. Thus, we propose that gamma frequency
oscillations represent a network state that introduces long-lasting synaptic
plasticity in a cell-specific manner
Weeds in the treated field - a realistic scenario for pollinator risk assessment?
In July 2013 the European Food Safety Authority (EFSA) released its final guidance on the risk assessment of plant protection products (PPPs) to bees1. One objective of the guidance was to produce a simple and cost effective first tier risk assessment scheme to ensure that the appropriate level of protection is achieved. However, recent impact analyses have indicated that the first tier of this risk assessment does not act effectively as a screen for compounds of low risk to bees. For example substances showing no toxicity to bees often fail the tier 1 risk assessment based on a worst-case exposure to flowering weeds inside the treated field. If realistic farming practices (e.g. tillage and herbicide applications) are considered, weeds are not usually prevalent in arable fields. It is therefore suggested that the scenarios in the guidance could be considered overly conservative and in some instances unrealistic. The EFSA guidance states that if <10% of the area of use is flowering weeds then the exposure route is not relevant in the 90th %ile case, and thus does not need to be considered. However, despite this, the option to generate data or refine assessments based on available data is questioned as no guidance for the assessment of the abundance of weeds is available. As part of an industry-led initiative we present and discuss the use of empirical evidence (i.e. occurrence and growth stage of weeds in control plots from herbicide efficacy field trials conducted for regulatory submission) to illustrate that the scenarios in the guidance document could be modified using currently available data to create a more effective tier 1 risk assessment and still ensure that the appropriate level of protection is achieved. We have demonstrated here that less than 2% of all weeds recorded in arable crop trials (represented here by wheat, oilseed rape, sugar beet, sunflower, potatoes, maize, peas and beans) are at a flowering growth stage; therefore in arable crops the flowering weeds scenario is not applicable for the 90th %ile exposure. For permanent crop trials (represented here by orchards and vines) 37% of weeds were recorded at a flowering growth stage. When the attractiveness and density data are considered, the percentage of attractive, flowering weeds which cover >10% of the ground area is only 12.3%, indicating that for permanent crops further investigation may be required as to whether this scenario is relevant
Two carbon fluxes to reserve starch in potato (Solanum tuberosum L.) tuber cells are closely interconnected but differently modulated by temperature
Parenchyma cells from tubers of Solanum tuberosum L. convert several externally supplied sugars to starch but the rates vary largely. Conversion of glucose 1-phosphate to starch is exceptionally efficient. In this communication, tuber slices were incubated with either of four solutions containing equimolar [U-14C]glucose 1-phosphate, [U-14C]sucrose, [U-14C]glucose 1-phosphate plus unlabelled equimolar sucrose or [U-14C]sucrose plus unlabelled equimolar glucose 1-phosphate. 14C-incorporation into starch was monitored. In slices from freshly harvested tubers each unlabelled compound strongly enhanced 14C incorporation into starch indicating closely interacting paths of starch biosynthesis. However, enhancement disappeared when the tubers were stored. The two paths (and, consequently, the mutual enhancement effect) differ in temperature dependence. At lower temperatures, the glucose 1-phosphate-dependent path is functional, reaching maximal activity at approximately 20 °C but the flux of the sucrose-dependent route strongly increases above 20 °C. Results are confirmed by in vitro experiments using [U-14C]glucose 1-phosphate or adenosine-[U-14C]glucose and by quantitative zymograms of starch synthase or phosphorylase activity. In mutants almost completely lacking the plastidial phosphorylase isozyme(s), the glucose 1-phosphate-dependent path is largely impeded. Irrespective of the size of the granules, glucose 1-phosphate-dependent incorporation per granule surface area is essentially equal. Furthermore, within the granules no preference of distinct glucosyl acceptor sites was detectable. Thus, the path is integrated into the entire granule biosynthesis. In vitro
14C-incorporation into starch granules mediated by the recombinant plastidial phosphorylase isozyme clearly differed from the in situ results. Taken together, the data clearly demonstrate that two closely but flexibly interacting general paths of starch biosynthesis are functional in potato tuber cells
Review of the genus Cobitis in the Middle East, with the description of eight new species (Teleostei: Cobitidae)
WOS: 000453850600001The diversity of Cobitis in the Middle East is reviewed, resulting in the recognition of 30 species, of which eight are described herein as new. Two species, C. amphilekta and C. kellei, seem to be extinct. Hypotheses on species-level diversity derived from distance and Poisson tree process analyses of DNA barcode data are tested against morphometric and morphological characters including colour patterns. For species pairs separated by small K2P distances in COI sequence data we follow a practitioner-oriented diagnostic species concept, in which we recognise species only if differentiated morphologically (including by colour pattern). For all 30 species we provide diagnoses and identification keys. Cobitis afifeae, new species, from the Buyuk Menderes River drainage in the Aegean Sea basin, is distinguished by having two laminae circularis in the male, a row of blotches below Z4, a small, roundish or comma-shaped black spot at the upper caudal-fin base, and elevated mental lobes. Cobitis aliyeae, new species, from the lower Seyhan and Ceyhan River drainages, is distinguished by having two laminae circularis in the male, the blotches in Z2 and Z4 anterior to the dorsal-fin origin usually well separated from each other, and the pigmentation in Z1 well distinguished from the pigmentation in Z2. Cobitis anabelae, new species, from the lower Orontes River drainage, is distinguished by having two laminae circularis in the male, the pigmentation in Z2 formed by small, brown spots, always much smaller than blotches in Z3, much smaller than the pupil diameter, Z2 and Z3 well separated, and no pigmentation below Z4. Cobitis erkakanae, new species, from the Golbasi Lakes, adjacent to the Ceyhan River drainage, is distinguished by having two laminae circularis in the male, no blotches below Z4, the blotches in Z2 and Z4 being horizontally elongated and often fused with adjacent ones, and the caudal fin with 4-6 wide, regularly-shaped, brown bands. Cobitis emrei, new species, from the Lake Sapanca basin is distinguished by having one lamina circularis in the male, a large black spot at the upper caudal-fin base, and Z3 fully covered by very small spots forming a sand-like pattern. Cobitis joergbohleni, new species, from the Sultan marshes in Central Anatolia is distinguished by having two laminae circularis in the male, and the flank colour pattern being completely disorganised, not following the Gambetta zones. Cobitis pirii, new species, from the endorheic Lake Egirdir basin and the Mediterranean Aksu and Kopru Rivers, is distinguished by having two laminae circularis in the male, a simple external part of the suborbital spine and two distinct rows of small blotches in Z4, one along the lateral midline and one distinctly below. Cobitis troasensis, new species, from the Tuzla River drainage, is distinguished by having one lamina circularis in the male and 25-36 small, comma-shaped brown blotches in Z4. A lectotype is designated for Cobitis battalgilae. As First Revisers, priority is given to Cobitis fahireae over C. kurui. Cobitis damlae and C. kurui are treated as synonyms of C. fahireae. Cobitis strumicae and C. taenia are recorded for the first time from Anatolia and C. saniae is newly documented from the Black Sea basin in Georgia. the Poisson tree process analysis of COI data proposed 31 groups, most of which could be distinguished by morphological characters. Cobitis troasensis is described based on morphological data alone.Leibniz Association Joint Initiative for Research and Innovation (SAW)We thank Mufit Ozulug (Istanbul) for allowing JF to participate in his many years of fieldwork in Turkey and Fusun Erk'akan (Ankara) and Michel Bariche (AUBM) for supporting us with the picture of the type of C. damlaeand a picture of C. levantina. Soheil Eagderi (Karaj) for allowing us to use his photos of Cobitis saniae and Ekatherina Vasil'eva (Moscow) as well as Hamed Mousavi-Sabet (Guilan) for allowing us to use their photos of the holotypes of C. amphilekta and C. avicennae. Many thanks to Baran Yogurtcuoglu (Ankara), Cuneyt Kaya (Rize) and Davut Turan (Rize) for help during fieldwork. Many thanks to Fusun Erk'akan (Ankara) and Ralf Thiel and Irina Eidus (ZMH) for allowing JF to examine materials under their care and Baran Yogurtcuoglu for helping us with a picture of the holotype of C. kurui and Teodor T. Nalbant (Bucharest) for gifting JF many drawings of loaches. Samvel Pipoyan (Yerevan), Anabel Perdices (Madrid) and Hamed Mousavi-Sabet (Guilan) supported us with molecular materials. Many thanks to Erhan Unlu (Diyarbakir), Cuneyt Kaya and Baran Yogurtcuoglu for unpublished information. Amina Brahimi (Liege) is thanked for producing the distribution map (Fig. 2) for us. This study is a product of the FREDIE project, supported by the Leibniz Association Joint Initiative for Research and Innovation (SAW)
Review of the genus Cobitis in the Middle East, with the description of eight new species (Teleostei: Cobitidae)
WOS: 000453850600001The diversity of Cobitis in the Middle East is reviewed, resulting in the recognition of 30 species, of which eight are described herein as new. Two species, C. amphilekta and C. kellei, seem to be extinct. Hypotheses on species-level diversity derived from distance and Poisson tree process analyses of DNA barcode data are tested against morphometric and morphological characters including colour patterns. For species pairs separated by small K2P distances in COI sequence data we follow a practitioner-oriented diagnostic species concept, in which we recognise species only if differentiated morphologically (including by colour pattern). For all 30 species we provide diagnoses and identification keys. Cobitis afifeae, new species, from the Buyuk Menderes River drainage in the Aegean Sea basin, is distinguished by having two laminae circularis in the male, a row of blotches below Z4, a small, roundish or comma-shaped black spot at the upper caudal-fin base, and elevated mental lobes. Cobitis aliyeae, new species, from the lower Seyhan and Ceyhan River drainages, is distinguished by having two laminae circularis in the male, the blotches in Z2 and Z4 anterior to the dorsal-fin origin usually well separated from each other, and the pigmentation in Z1 well distinguished from the pigmentation in Z2. Cobitis anabelae, new species, from the lower Orontes River drainage, is distinguished by having two laminae circularis in the male, the pigmentation in Z2 formed by small, brown spots, always much smaller than blotches in Z3, much smaller than the pupil diameter, Z2 and Z3 well separated, and no pigmentation below Z4. Cobitis erkakanae, new species, from the Golbasi Lakes, adjacent to the Ceyhan River drainage, is distinguished by having two laminae circularis in the male, no blotches below Z4, the blotches in Z2 and Z4 being horizontally elongated and often fused with adjacent ones, and the caudal fin with 4-6 wide, regularly-shaped, brown bands. Cobitis emrei, new species, from the Lake Sapanca basin is distinguished by having one lamina circularis in the male, a large black spot at the upper caudal-fin base, and Z3 fully covered by very small spots forming a sand-like pattern. Cobitis joergbohleni, new species, from the Sultan marshes in Central Anatolia is distinguished by having two laminae circularis in the male, and the flank colour pattern being completely disorganised, not following the Gambetta zones. Cobitis pirii, new species, from the endorheic Lake Egirdir basin and the Mediterranean Aksu and Kopru Rivers, is distinguished by having two laminae circularis in the male, a simple external part of the suborbital spine and two distinct rows of small blotches in Z4, one along the lateral midline and one distinctly below. Cobitis troasensis, new species, from the Tuzla River drainage, is distinguished by having one lamina circularis in the male and 25-36 small, comma-shaped brown blotches in Z4. A lectotype is designated for Cobitis battalgilae. As First Revisers, priority is given to Cobitis fahireae over C. kurui. Cobitis damlae and C. kurui are treated as synonyms of C. fahireae. Cobitis strumicae and C. taenia are recorded for the first time from Anatolia and C. saniae is newly documented from the Black Sea basin in Georgia. the Poisson tree process analysis of COI data proposed 31 groups, most of which could be distinguished by morphological characters. Cobitis troasensis is described based on morphological data alone.Leibniz Association Joint Initiative for Research and Innovation (SAW)We thank Mufit Ozulug (Istanbul) for allowing JF to participate in his many years of fieldwork in Turkey and Fusun Erk'akan (Ankara) and Michel Bariche (AUBM) for supporting us with the picture of the type of C. damlaeand a picture of C. levantina. Soheil Eagderi (Karaj) for allowing us to use his photos of Cobitis saniae and Ekatherina Vasil'eva (Moscow) as well as Hamed Mousavi-Sabet (Guilan) for allowing us to use their photos of the holotypes of C. amphilekta and C. avicennae. Many thanks to Baran Yogurtcuoglu (Ankara), Cuneyt Kaya (Rize) and Davut Turan (Rize) for help during fieldwork. Many thanks to Fusun Erk'akan (Ankara) and Ralf Thiel and Irina Eidus (ZMH) for allowing JF to examine materials under their care and Baran Yogurtcuoglu for helping us with a picture of the holotype of C. kurui and Teodor T. Nalbant (Bucharest) for gifting JF many drawings of loaches. Samvel Pipoyan (Yerevan), Anabel Perdices (Madrid) and Hamed Mousavi-Sabet (Guilan) supported us with molecular materials. Many thanks to Erhan Unlu (Diyarbakir), Cuneyt Kaya and Baran Yogurtcuoglu for unpublished information. Amina Brahimi (Liege) is thanked for producing the distribution map (Fig. 2) for us. This study is a product of the FREDIE project, supported by the Leibniz Association Joint Initiative for Research and Innovation (SAW)
Alburnus goekhani, a new species of bleak from the Anatolian Black Sea basin (Teleostei: Leuciscidae)
Alburnus goekhani, new species, is described from the Yesilirmak and Kizilirmak River drainages. It belongs to the A. alburnus species group and is distinguished from other species in this group in Anatolia by having 48-56 + 2-3 scales in the lateral-line, 12-15 gill rakers, a distinct dark lateral stripe along the flank on live and preserved specimens and the anal-fin origin situated below the branched dorsal-fin ray 6-8. Alburnus goekhani is also well distinguished from other Alburnus species by its DNA barcode sequence
A practical approach to revise the Oxynoemacheilus bergianus species group (Teleostei: Nemacheilidae)
The Oxynoemacheilus bergianus species group is revised based on tree topology (ML, NJ, MP), distance (K2P and ASAP) and Poisson tree process analyses of DNA barcode data tested against morphometric and morphological characters including colour patterns. The O. bergianus species group is distinguished from other Oxynoemacheilus groups based on morphological characters: its constituent species have a slender caudal peduncle, a suborbital flap in the male, a mottled or blotched colour pattern, and lack bold, black spots on the caudal-fin base. It is also supported as a monophyletic unit in our molecular analysis. The O. bergianus group includes 10 molecular clades following congruently well-supported NJ, MP and ML based entities. Species described as O. bergianus, O. banarescui, O. erdali, O. fatsaensis, O. samanticus, and O. simavicus from Turkey, O. lenkoranensis from Azerbaijan, and O. longipinnis and O. parvinae from Iran belong to this species group. The group includes also four unnamed molecular clades. We were unable to detect external differences between any of the molecular clades in colour pattern or any morphometric or morphological characters examined. In the 10 molecular clades in the O. bergianus species group, the intraclade K2P distance ranges from 0.0-1.8% while the distances between molecular clades ranges from 0.6-5.9%. To resolve the species diversity of this group, we also analysed the intraspecific and interspecific variability in the K2P distance of DNA barcode data from 53 other Oxynoemacheilus species. Here, the intraspecific variability ranges from 0.0-2.4% while the interspecific K2P distance ranges from 1.2-20.8%. In the O. bergianus species group, only four groups are detected by the mPTP species delimitation approach distinguished by a K2P distance of 2.9% or more. We treat these four groups as valid species, corresponding to O. banarescui, O. bergianus, O. fatsaensis, and O. simavicus. Oxynoemacheilus samanticus from the Kizilirmak and Seyhan drainages, O. lenkoranensis from the Caspian basin, O. erdali from the Euphrates, and O. longipinnis and O. parvinae from the Tigris drainage are treated as synonyms of O. bergianus. Fishes from an unnamed molecular clade from the upper Tigris, and from a second unnamed clade from the upper Euphrates, are both identified as O. bergianus. Oxynoemacheilus bergianus might be a junior synonym of O. bergi from the Kura. The distribution range of O. simavicus, described from the Simav drainage in the Marmara basin, is expanded to the east and two molecularly differentiated population groups occur in the Sakarya drainage, the Buyuk Melen River and potentially in other adjacent coastal streams. Oxynoemacheilus fatsaensis, described from the coastal stream Elekci in northern Anatolia, is also widespread in the Yesilirmak drainage. Morphological characters proposed to distinguish O. fatsaensis from the other species of the O. bergianus group could not be confirmed by our data on fishes from the Yesilirmak. This study also discusses the theoretical background, our reasons for conducting this revision in the way we did, and what the alternatives would be
Review of the Oxynoemacheilus tigris group with the description of two new species from the Euphrates drainage (Teleostei: Nemacheilidae)
WOS: 000469111000002PubMed: 31717077The Oxynoemacheilus tigris species group is reviewed, resulting in the recognition of six species, of which two are described herein as new. Oxynoemacheilus tigris is known from the endorheic Qweik River and the Merziman River, which is a tributary of the western Euphrates. Oxynoemacheilus ercisianus is endemic to the endorheic Lake Van basin and O. hazarensis is endemic to Lake Hazar basin in the upper Tigris drainage. Oxynoemacheilus kaynaki is widespread in the Euphrates drainage. the two undescribed species occur in the Euphrates drainage. Oxynoemacheilus arsaniasus, new species, from the Murat River and the upper Karasu (Mus) River drainage, is distinguished from other species of the O. tigris group by having a bold, black, irregularly-shaped bar at the caudal-fin base, an incomplete lateral line and a scaleless body. Oxynoemacheilus muefiti, new species, from the upper Murat River drainage and a tributary to the Ataturk reservoir, is most similar to O. ercisianus, from which it is distinguished by a more slender body and a shallower dorsal adipose crest. According to our molecular data, the Qweik population of O. tigris is suspected to be introgressed by O. namiri from the Orontes drainage. Oxynoemacheilus erdali is identified as a synonym of O. bergianus as we were unable to find differences between the two species.Leibniz Association Joint Initiative for Research and Innovation (SAW)We thank Esra Baycelebi and Zuleyha Akpynar (Rize) for their help during fieldworks and in the laboratory. Hamed Mousavi-Sabet (Guilan) for supporting us with some tissues from his collection and Mufit Ozulug (Istanbul) allowed JF to participate in his many years of fieldwork. Many thanks also to two reviewers, who took the burden to read the manuscript, for useful comments. This study is a product of the FREDIE project, supported by the Leibniz Association Joint Initiative for Research and Innovation (SAW)
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