Combinatorial ShcA docking interactions support diversity in tissue morphogenesis

Changes in protein-protein interactions may allow polypeptides to perform unexpected regulatory functions. Mammalian ShcA docking proteins have amino-terminal phosphotyrosine (pTyr) binding (PTB) and carboxyl-terminal Src homology 2 (SH2) domains, which recognize specific pTyr sites on activated receptors, and a central region with two phosphorylated tyrosine-X-asparagine (pYXN) motifs (where X represents any amino acid) that each bind the growth factor receptor-bound protein 2 (Grb2) adaptor. Phylogenetic analysis indicates that ShcA may signal through both pYXN-dependent and -independent pathways. We show that, in mice, cardiomyocyte-expressed ShcA directs mid-gestational heart development by a PTB-dependent mechanism that does not require the pYXN motifs. In contrast, the pYXN motifs are required with PTB and SH2 domains in the same ShcA molecule for the formation of muscle spindles, skeletal muscle sensory organs that regulate motor behavior. Thus, combinatorial differences in ShcA docking interactions may yield multiple signaling mechanisms to support diversity in tissue morphogenesis.     

Pollen sterility induced by ethrel and its utilization in hybridization of wheat

Summary In 1974 and 1975 gametocidal effects of Ethrel were investigated under field conditions in the spring wheat cv. Zlatka. In experimental plants grain setting per spikelet and ear as well as ability to be cross-pollinated were ascertained.As compared with the control, treated variants achieved more than 90% sterility. Female fertility was not affected and cross-pollination was possible. Genetical check showed that the best variants, when cross-pollinated, produced 50–55% hybrids; grain setting, however, was brought down by more than 37%. As a result of Ethrel treatment haulm length was reduced and the vegetation period was somewhat prolonged.     

Bayesian modelling suggests that the sterlet (Acipenser ruthenus,Linnaeus 1758) population is ageing in the middle Danube River

1. In the past, sturgeons played an important role in commercial and recreational fisheries in the Danube River and its tributaries. Human impacts in the Danube River Basin coupled with exploitation of sturgeon stocks led to all species being either locally extinct, critically endangered or of unknown status.
2. Sterlet (Acipenser ruthenus, Linnaeus 1758) is the last known sturgeon species occurring in the upper and middle Danube; however, the population of this species is considered unbalanced and decreasing since the beginning of the twenty-first century.
3. The decline of sturgeon stocks has been noted before owing to their economic importance. With commercial fisheries being forbidden in the Slovak section of the Danube River, there is generally no information available about the status of what is considered a local population.
4. Databases containing recreational catch of sterlet (2003–2018) and historical records of commercial harvest (1961–1990) were used to describe the trend in the weight and number of sterlet caught over the following years.
5. Modelling indicated that the number of fish caught each year appears to be lower, while the average weight of each individual is increasing. This might suggest that the population is ageing.
6. Although older individuals can contribute a great deal more to spawning because they produce a greater number of eggs, several problems are apparent. The number of spawners might be decreasing as a result of bycatch or fishing, their ability to spawn might be obstructed, or annual recruitment may fail owing to unpredictable events.
7. Although restocking programmes are in place to help maintain the sterlet population in the Danube River, their efficiency seems to be drastically low. In fact, restocking could be of little value unless studies on the availability of key habitats are conducted and their protection and restoration are ensured.

     

Ammonia autointoxication of common carp: case studies

Three case studies of ammonia autointoxication of the common carp (Cyprinus carpio L.) are described. In the first case, carp yearlings with a full digestive tract were transferred during the growing period from pond water (22°C) to tap water (17°C). In the second case, marketable carp were transferred from the fishing ground of a pond (18°C) to a storage pond (10–12°C). Harvest was performed in late September when the fish were still ingesting natural feed. In the third case, marketable carp after storage for 1 month were transferred to storage ponds with markedly lower water temperature. Stress because of harvest and handling also occurred in this case. In all cases, highly increased concentrations of ammonia were found in the blood plasma of the fish (mean ± SD 1760 ± 350 μmol L⁻¹ in the first case, 870 ± 540 μmol L⁻¹ in the second case, and 880 ± 150 μmol L⁻¹ in the third case). Highly congested, dark-red coloured, oedematous gills were observed for all specimens. We can avoid similar cases of ammonia autointoxication by protection of fish from sudden changes of temperature during rearing, harvesting, and handling.     

Colonization of chemical factory wastes by soil nematodes

Soil nematodes were studied in 39- and 49-year-old “red” dumps mainly composed of Fe₂O₃ waste pyrite remnants from production of sulphuric and other acids, and in a 84-year-old “white” dump mainly composed of CaCO₃ material from soda production. The youngest stage of spontaneous biological succession contained moss–lichen patches which were mainly inhabited by bacterivorous nematodes (Acrobeloides nanus, Panagrolaimus rigidus, Rhabditis terricola, Bursilla monhystera) in very low abundance (about 50×10³ ind m⁻²). Invasion of grass resulted in increase of bacterivorous nematodes up to several millions  ind m⁻² but with considerable seasonal fluctuations. Nematode assemblages diversified in sites colonized by various deciduous trees and Paratylenchus straeleni was the dominant plant parasitic nematode. In site with stabilized grass carpet on the “white” dump dominant nematodes were Geocenamus quadrifer and Pungentus engadinensis. Eudorylaimus spp. first appeared in 49-year-old dump but their populations remained very low (1–9×10³ ind m⁻²). Some species found in control deciduous forests on natural soils (e.g. Xenocriconemella macrodora, Cephalenchus hexalineatus, Tylolaimophorus minor, Ogma menzeli, Hoplotylus femina) did not colonize deposits. Natural succession of nematodes on chemical waste materials was very slow and even after about 80 years their communities under deciduous trees showed many differences from those in nearby semi-natural mixed forests.     

Short term pharmacological immobilization in macaque monkeys

ObjectiveTo develop a safe and effective immobilization protocol in rhesus monkeys, which is not based on dissociative anaesthetic agent.Study designProspective, randomised, experimental trial.AnimalsTwenty rhesus monkeys, weighing 2.6–8.0 kg, 1–3 years of age, of both sexes.MethodsThe monkeys received 50 μg kg^?1 medetomidine, 0.25 mg kg^?1 midazolam and 5 μg kg^?1 fentanyl with 150 IU hyaluronidase intramuscularly (IM). The animals were closely observed for behavioural changes and reaction to sound stimulus. Pulse rate and oxygen saturation of haemoglobin (SpO₂) were monitored every 5 minutes, for 20 minutes. After this period, 250 μg kg^?1 atipamezole or a placebo was administered IM and behavioural changes were closely observed.ResultsFull immobilization was observed after mean 269 ± SD 116 seconds. Ten minutes after injection mean arterial oxygen saturation of haemoglobin was 94 ± 4%, but did not fall significantly further. The median pulse rate was 116 beats minute^?1 5 minutes after the administration of the drug. This level further decreased to a median level of 108 beats minute^?1 20 minutes after the drug's administration. The median time to recover from immobilization was significantly shorter after atipamezole administration when compared to placebo (2.7 versus 55 minutes). All animals awoke smoothly and no side effects such as vomiting or agitation were observed.ConclusionsShort term and reversible pharmacological immobilization was achieved using combination of midazolam, medetomidine, and fentanyl.Clinical relevanceThe present study demonstrates that 20-minute pharmacological immobilization with a combination of midazolam, medetomidine, and fentanyl is feasible in rhesus monkeys with minimal effect on heart rate.     

Blood parasites of birds in Central Europe. 1. Survey of literature. The incidence in domestic birds and general remarks to the incidence in wild birds

This paper constitutes an introduction to the forthcoming series of publications summing up the present store of knowledge on the incidence and ecology of avian haematozoa in Central Europe. The paper contains bibliography dealing with the incidence of these parasites in the region studied. The problem of the incidence of blood parasites in domestic birds is discussed in detail. The incidence of blood parasites in wild birds is only briefly outlined as it is to be treated in detail in forthcoming papers.