Free-Living Marine Interstitial Hypotrichid Ciliates from Jubail Marine Wildlife Sanctuary in the Arabian Gulf

Sediment samples were collected at low tide from various localities of the Jubail Marine Wildlife Sanctuary in the Arabian Gulf on several occasions during l996-l997 for the study of the marine interstitial ciliate fauna of the Sanctuary. Twenty three species belonging to the order Hypotrichida were identified after protargol impregnation, 20 of which represent new records of the fauna of Saudi Arabia, and of the Arabian Gulf at large. The distribution of each species is compared to those in similar habitats worldwide. The present study increases the total known number of hypotrichid ciliates species in Saudi Arabia to 40 species

The origins and spread of domestic horses from the Western Eurasian steppes

Analysis of 273 ancient horse genomes reveals that modern domestic horses originated in the Western Eurasian steppes, especially the lower Volga-Don region.Domestication of horses fundamentally transformed long-range mobility and warfare(1). However, modern domesticated breeds do not descend from the earliest domestic horse lineage associated with archaeological evidence of bridling, milking and corralling(2-4) at Botai, Central Asia around 3500 bc(3). Other longstanding candidate regions for horse domestication, such as Iberia(5) and Anatolia(6), have also recently been challenged. Thus, the genetic, geographic and temporal origins of modern domestic horses have remained unknown. Here we pinpoint the Western Eurasian steppes, especially the lower Volga-Don region, as the homeland of modern domestic horses. Furthermore, we map the population changes accompanying domestication from 273 ancient horse genomes. This reveals that modern domestic horses ultimately replaced almost all other local populations as they expanded rapidly across Eurasia from about 2000 bc, synchronously with equestrian material culture, including Sintashta spoke-wheeled chariots. We find that equestrianism involved strong selection for critical locomotor and behavioural adaptations at the GSDMC and ZFPM1 genes. Our results reject the commonly held association(7) between horseback riding and the massive expansion of Yamnaya steppe pastoralists into Europe around 3000 bc(8,9) driving the spread of Indo-European languages(10). This contrasts with the scenario in Asia where Indo-Iranian languages, chariots and horses spread together, following the early second millennium bc Sintashta culture(11,12).Descriptive and Comparative Linguistic

The origins and spread of domestic horses from the Western Eurasian steppes

Domestication of horses fundamentally transformed long-range mobility and warfare. However, modern domesticated breeds do not descend from the earliest domestic horse lineage associated with archaeological evidence of bridling, milking and corralling at Botai, Central Asia around 3500 bc. Other longstanding candidate regions for horse domestication, such as Iberia and Anatolia, have also recently been challenged. Thus, the genetic, geographic and temporal origins of modern domestic horses have remained unknown. Here we pinpoint the Western Eurasian steppes, especially the lower Volga-Don region, as the homeland of modern domestic horses. Furthermore, we map the population changes accompanying domestication from 273 ancient horse genomes. This reveals that modern domestic horses ultimately replaced almost all other local populations as they expanded rapidly across Eurasia from about 2000 bc, synchronously with equestrian material culture, including Sintashta spoke-wheeled chariots. We find that equestrianism involved strong selection for critical locomotor and behavioural adaptations at the GSDMC and ZFPM1 genes. Our results reject the commonly held association between horseback riding and the massive expansion of Yamnaya steppe pastoralists into Europe around 3000 bc driving the spread of Indo-European languages. This contrasts with the scenario in Asia where Indo-Iranian languages, chariots and horses spread together, following the early second millennium bc Sintashta culture

Free-Living Marine Interstitial Hypotrichid Ciliates from Jubail Marine Wildlife Sanctuary in the Arabian Gulf

Sediment samples were collected at low tide from various localities of the Jubail Marine Wildlife Sanctuary in the Arabian Gulf on several occasions during l996-l997 for the study of the marine interstitial ciliate fauna of the Sanctuary. Twenty three species belonging to the order Hypotrichida were identified after protargol impregnation, 20 of which represent new records of the fauna of Saudi Arabia, and of the Arabian Gulf at large. The distribution of each species is compared to those in similar habitats worldwide. The present study increases the total known number of hypotrichid ciliates species in Saudi Arabia to 40 species

Problems in the systematic classification of some species of hypotrichous (Ciliophora, Spirotrichea).

For a very long time the higher-level systematics of hypotrichs (= stichotrichs according to Small & Lynn) followed mainly the ventral cirral pattern. Since about three decades, several other morphological and ontogenetic features are successfully used, for example, the dorsal kinety pattern (e.g., kinety fragmentation of oxytrichids) or the rigid body of the stylonychines. Many species can be assigned without any problems to higher taxa like, e.g., the stylonychines, the urostyloids, or the amphisiellids because they show at least one apomorphy of a suprageneric taxon. On the other hand, a considerable number of species is known which cannot be classified in a certain group. Two types can be distinguished, namely (i) those species which lack any higher-level apomorphy (e.g., Saudithrix terricola Foissner et al.); and (ii) those which have two or more apomorphies, which, however, assign them to different taxa. Examples for the second type are (i) Neokeronopsis spectabilis (Kahl) which has a midventral pattern like the urostyloids and a dorsal kinety fragmentation like the oxytrichids; and (ii) a new, Uroleptus-like species with a rigid body which would assign it to the stylonychines. In contrast, the molecular data of this species suggest a close relationship with Oxytricha. Financial support was provided by a grant (APART; Austrian Programme for Advanced Research and Technology, Project 10940) of the Austrian Academy of Sciences, Vienna, to H. Berger, and by KACST (King Abdulaziz City for Science Technology; Project LGP-7-9), Riyadh, Saudi Arabia for K. A. S. ALRhasheid and W. Foissner

Light and electron microscopy of eimeria magna perard, 1925 infecting the house Rabbit, Oryctolagus cuniculus from Saudi Arabia: II. Gamogony and Oocyst wall formation

Gamogony and oocyst wal1 formation of Eimeria magna Perard, 1925 were described by light and electron microscopy for the first time in the smal1 intestinal epithelium of experimental1y infected house rabbits, Oryctolagus cuniculus from three different regions in Saudi Arabia. Sequence of events started as sexual1y differentiated fourth and fifth generation merozoites transformed into micro- or macrogamonts at 125 h.p.i., where most of the apicomplexan organel1es have been disappeared gradual1y. Microgamonts were recognizable by the presence of peripheral1y arranged nuclei and the presence of one or two centrioles between each nucleus and the limiting membrane of the gamont, while macrogamonts were recognized by the presence of wal1-forming bodies of types I and II. Both microgametogenesis and macrogametogenesis had two phases, the growth and differentiation phases. Up to 150-250 microgametes were produced per microgamont, each had 2 flagel1a. Wal1-forming bodies II and lipid globules were the first cytoplasmic inclusions to appear characterizing the development of macrogamonts. Wal1-forming bodies II, which appeared at first, were osmiophilic and distributed homogenously. Wal1-forming bodies I, which appeared later, were smal1er & distributed peripheral to the walI-forming bodies II. Oocyst wal1 formation occurred by union of the wal1 forming bodies of each type together and resulting in the formation of the bilayered oocyst wall

Acclimation to heat and drought - lessons to learn from the date palm (<em>Phoenix dactylifera</em>).

In the present study, we investigated the responses of date palm (Phoenix dactylifera) to drought and heat as single stressors and in combination. We tested the hypotheses (i) that heat and drought enhance the capacity of the antioxidative system, and (ii) that due to the high stress tolerance of date palm, the plants&#39; redox state will be widely unaffected, and (iii) that heat but not drought changes the plants&#39; fatty acid composition and biosynthesis of isoprene, both contributing to the stabilization of membrane integrity. Photosynthesis was only weakly affected by both stresses, whereas the levels of the antioxidants ascorbate and glutathione in leaves dropped. This drop was, however, over-compensated by increased activities of glutathione reductase, an important enzyme of the antioxidative system. The plants&#39; redox state was unaffected by stress as indicated by unchanged H2O2 levels. Because we do not know the concentration of isoprene at its site of action, isoprene emission might provide indirect hints on its possible functions. Isoprene emission strongly increased due to heat indicating its possible role as an antioxidant and for stabilization of thylakoid membranes. Fatty acids only reacted in response to drought. We conclude that the high heat and drought tolerance of date palm is the consequence of a concerted action of the antioxidative system, mainly based on enzyme activities and the assumed antioxidative effects of isoprene as well as adjustments in the fatty acid composition

The desert plant <em>Phoenix dactylifera</em> closes stomata via nitrate-regulated SLAC1 anion channel.

Date palm Phoenix dactylifera is a desert crop well adapted to survive and produce fruits under extreme drought and heat. How are palms under such harsh environmental conditions able to limit transpirational water loss? Here, we analysed the cuticular waxes, stomata structure and function, and molecular biology of guard cells from P.&nbsp;dactylifera. To understand the stomatal response to the water stress phytohormone of the desert plant, we cloned the major elements necessary for guard cell fast abscisic acid (ABA) signalling and reconstituted this ABA signalosome in Xenopus oocytes. The PhoenixSLAC1-type anion channel is regulated by ABA kinase PdOST1. Energy-dispersive X-ray analysis (EDXA) demonstrated that date palm guard cells release chloride during stomatal closure. However, in Cl(-) medium, PdOST1 did not activate the desert plant anion channel PdSLAC1 per&nbsp;se. Only when nitrate was present at the extracellular face of the anion channel did the OST1-gated PdSLAC1 open, thus enabling chloride release. In the presence of nitrate, ABA enhanced and accelerated stomatal closure. Our findings indicate that, in date palm, the guard cell osmotic motor driving stomatal closure uses nitrate as the signal to open the major anion channel SLAC1. This initiates guard cell depolarization and the release of anions together with potassium

Understanding the molecular basis of salt sequestration in epidermal bladder cells of <em>Chenopodium quinoa</em>.

Soil salinity is destroying arable land and is considered to be one of the major threats to global food security in the 21st century. Therefore, the ability of naturally salt-tolerant halophyte plants to sequester large quantities of salt in external structures, such as epidermal bladder cells (EBCs), is of great interest. Using Chenopodium quinoa, a pseudo-cereal halophyte of great economic potential, we have shown previously that, upon removal of salt bladders, quinoa becomes salt sensitive. In this work, we analyzed the molecular mechanism underlying the unique salt dumping capabilities of bladder cells in quinoa. The transporters differentially expressed in the EBC transcriptome and functional electrophysiological testing of key EBC transporters in Xenopus oocytes revealed that loading of Na+ and Cl- into EBCs is mediated by a set of tailored plasma and vacuole membrane-based sodium-selective channel and chloride-permeable transporter

<研究>經濟的合理主義ノ基礎

The field of population genetics is rapidly moving into population genomics as the quantity of data generated by high-throughput sequencing platforms increases. In this study, we used restriction-site-associated DNA sequencing (RADSeq) to recover genomewide genotypes from 70 white-beaked (Lagenorhynchus albirostris) and 43 Atlantic white-sided dolphins (L. acutus) gathered throughout their north-east Atlantic distribution range. Both species are at a high risk of being negatively affected by climate change. Here, we provide a resource of 38 240 RAD-tags and 52 981 nuclear SNPs shared between both species. We have estimated overall higher levels of nucleotide diversity in white-sided (π = 0.0492 ± 0.0006%) than in white-beaked dolphins (π = 0.0300 ± 0.0004%). White-sided dolphins sampled in the Faroe Islands, belonging to two pods (N = 7 and N = 11), showed similar levels of diversity (π = 0.0317 ± 0.0007% and 0.0267 ± 0.0006%, respectively) compared to unrelated individuals of the same species sampled elsewhere (e.g. π = 0.0285 ± 0.0007% for 11 Scottish individuals). No evidence of higher levels of kinship within pods can be derived from our analyses. When identifying the most likely number of genetic clusters among our sample set, we obtained an estimate of two to four clusters, corresponding to both species and possibly, two further clusters within each species. A higher diversity and lower population structuring was encountered in white-sided dolphins from the north-east Atlantic, in line with their preference for pelagic waters, as opposed to white-beaked dolphins that have a more patchy distribution, mainly across continental shelves