Differences in potassium uptake in grapevine varieties: Reasons and perspectives

The varietal differences in potassium uptake in two grapevine cultivars (Vitis vinifera L. cvs Leányka and Ezerjó) were studied by measuring K (86Rb) influx rates under near-equilibrium conditions. For this purpose, one-node cuttings were rooted and grown in nutrient solutions with different K supplies. The transport data are discussed along with K, Na, Mg and Ca contents of roots, petioles and leaf blades. It was found that the effective K-utilizer variety, Leányka, possesses efficient uptake and translocation mechanisms while these transport systems were lacking in the inefficient K-utilizer Ezerjó. Since the data presented are in good agreement with practical experiences for the utilization of K by the two cultivars, the method seems to be suitable for the selection of the most effective K-utilizer varieties

Naïve hosts of avian brood parasites accept foreign eggs, whereas older hosts fine-tune foreign egg discrimination during laying

BACKGROUND: Many potential hosts of social parasites recognize and reject foreign intruders, and reduce or altogether escape the negative impacts of parasitism. The ontogenetic basis of whether and how avian hosts recognize their own and the brood parasitic eggs remains unclear. By repeatedly parasitizing the same hosts with a consistent parasitic egg type, and contrasting the responses of naïve and older breeders, we studied ontogenetic plasticity in the rejection of foreign eggs by the great reed warbler (Acrocephalus arundinaceus), a host species of the common cuckoo (Cuculus canorus). RESULTS: In response to experimental parasitism before the onset of laying, first time breeding hosts showed almost no egg ejection, compared to higher rates of ejection in older breeders. Young birds continued to accept foreign eggs when they were subjected to repeated parasitism, whereas older birds showed even higher ejection rates later in the same laying cycle. CONCLUSIONS: Our results are consistent with the hypotheses that (i) naïve hosts need to see and learn the appearance of their own eggs to discriminate and reject foreign eggs, whereas (ii) experienced breeders possess a recognition template of their own eggs and reject parasitic eggs even without having to see their own eggs. However, we cannot exclude the possibility that other external cues and internal processes, accumulated simply with increasing age, may also modify age-specific patterns in egg rejection (e.g. more sightings of the cuckoo by older breeders). Future research should specifically track the potential role of learning in responses of individual hosts between first and subsequent breeding attempts by testing whether imprinting on a parasitized clutch reduces the rates of rejecting foreign eggs in subsequent parasitized clutches

An improved bound for the monochromatic cycle partition number

AbstractImproving a result of Erdős, Gyárfás and Pyber for large n we show that for every integer r⩾2 there exists a constant n0=n0(r) such that if n⩾n0 and the edges of the complete graph Kn are colored with r colors then the vertex set of Kn can be partitioned into at most 100rlogr vertex disjoint monochromatic cycles

Tularemia and Plague Survey in Rodents in Earthquake Zones in Southeastern Iran

OBJECTIVES: Earthquakes are one the most common natural disasters that lead to increased mortality and morbidity from transmissible diseases, partially because the rodents displaced by an earthquake can lead to an increased rate of disease transmission. The aim of this study was to evaluate the prevalence of plague and tularemia in rodents in the earthquake zones in southeastern Iran. METHODS: In April 2013, a research team was dispatched to explore the possible presence of diseases in rodents displaced by a recent earthquake magnitude 7.7 around the cities of Khash and Saravan in Sistan and Baluchestan Province. Rodents were trapped near and in the earthquake zone, in a location where an outbreak of tularemia was reported in 2007. Rodent serums were tested for a serological survey using an enzyme-linked immunosorbent assay. RESULTS: In the 13 areas that were studied, nine rodents were caught over a total of 200 trap-days. Forty-eight fleas and 10 ticks were obtained from the rodents. The ticks were from the Hyalomma genus and the fleas were from the Xenopsylla genus. All the trapped rodents were Tatera indica. Serological results were negative for plague, but the serum agglutination test was positive for tularemia in one of the rodents. Tatera indica has never been previously documented to be involved in the transmission of tularemia. CONCLUSIONS: No evidence of the plague cycle was found in the rodents of the area, but evidence was found of tularemia infection in rodents, as demonstrated by a positive serological test for tularemia in one rodent

Why should Common Cuckoos Cuculus canorus lay their eggs in host nests?

Capsule Brood parasitic Common Cuckoo Cuculus canorus chicks hatch earlier than the nestlings of their Great Reed Warbler Acrocephalus arundinaceus hosts, but hatching priority is less certain when cuckoo eggs are laid after the onset of host incubation. Aim To reveal by field observations what the optimal stage is for cuckoos to lay their eggs in relation to the host laying cycle to ensure prior hatching of the parasitic chicks. Methods We monitored the hatching of cuckoo chicks in relation to the hosts’ laying stage at which the cuckoo eggs appeared and also monitored host incubation behaviour. Results Great Reed Warblers incubated more on day 5 after the host's onset of laying relative to day 3. All cuckoo eggs hatched earlier than hosts when they were laid prior to the onset of host incubation (day 4). Cuckoo eggs also maintained hatching priority in about 2/3 of the nests when laid on days 5-6. Conclusions Most cuckoo eggs are laid prior to the onset of host incubation, and this, together with other adaptive mechanisms, ensures the prior hatching of cuckoo eggs. Cuckoo eggs laid after incubation lose the advantage of prior hatching in clutch in ca. 30% of nests

Parking functions, labeled trees and DCJ sorting scenarios

In genome rearrangement theory, one of the elusive questions raised in recent years is the enumeration of rearrangement scenarios between two genomes. This problem is related to the uniform generation of rearrangement scenarios, and the derivation of tests of statistical significance of the properties of these scenarios. Here we give an exact formula for the number of double-cut-and-join (DCJ) rearrangement scenarios of co-tailed genomes. We also construct effective bijections between the set of scenarios that sort a cycle and well studied combinatorial objects such as parking functions and labeled trees.Comment: 12 pages, 3 figure