Survival and redox activity of Friedmanniomyces endolithicus, an Antarctic endemic black meristematic fungus,after gamma rays exposure

Despite living organisms are not exposed to acute ionizing radiation under natural conditions, some exhibit a high radiation resistance. Understanding this phenomenon is important for assessing the impact of radiation-related accidents, occupational exposures and space missions. In this context, in this study we analyzed the effect of gamma rays on the Antarctic cryptoendolithic melanized fungus Friedmanniomyces endolithicus CCFEE 5208 and demonstrated its resistance to acute doses of gamma radiation (up to 400 Gy), accompanied by increase in metabolic activity.     

Cumulative ecological effects of a Neotropical reservoir cascade across multiple assemblages

Kettle holes are often abundant within agriculturally used moraine landscapes. They are highly enriched with nutrients and considered hotspots of carbon turnover. However, data on their primary productivity remain rare. We analysed two kettle holes typical to Germany with common aquatic plant communities during one year. We hypothesised that gross primary production (GPP) rates would be high compared to other temperate freshwater ecosystems, leading to high sediment deposition. Summer GPP rates (4.5–5.1 g C m^?2 day^?1) were higher than those of most temperate freshwater systems, but GPP rates were reduced by 90% in winter. Macrophytes dominated GPP from May to September with emergent macrophytes accounting for half of the GPP. Periphyton contributed to most of the system GPP throughout the rest of the year. Sediment deposition rates were high and correlated with GPP in one kettle hole. In contrast, due to prolonged periods of anoxia, aerobic sediment mineralisation was low while sediment phosphorus release was significant. Our results suggest that kettle holes have a high potential for carbon burial, provided they do not fully dry up during warm years. Due to their unique features, they should not be automatically grouped with ponds and shallow lakes in global carbon budget estimates.     

The golden jackal (<Emphasis Type="Italic">Canis aureus</Emphasis>) in Bosnia and Herzegovina: density of territorial groups,population trend and distribution range

In this article, we present the results of the first systematic surveys of golden jackals in Bosnia and Herzegovina (B&H). The population status and distribution of the golden jackal (Canis aureus) in B&H was largely unknown, and the few existing literature records mention their presence at only five localities in the country. We interviewed managers of all the hunting grounds in B&H and reviewed available jackal hunting records from 2000 to 2016. In total, we collected 212 records of legally harvested jackals. We observed an increasing trend of harvested jackals in B&H (on average 35% annual increase) during this same period. Using the acoustic (playback) method, we confirmed the presence of 80 territorial jackal groups along six transects covering 3081 km². We estimated density to be a minimum of 0.33 groups/10 km² in northern B&H and 0.10 groups/10 km² in central B&H. Jackal groups were located at significantly lower altitudes with respect to available area along the transects. We present a distribution map of confirmed jackal occurrences in B&H, which indicates that the core area of jackal distribution in the country is currently located along the Sava River and its tributaries in the northern part of B&H. Jackals are sporadically present in the rest of the country, where gray wolves (Canis lupus) probably limit their presence. In total, jackal presence has been detected in 19% (109 out of 586) of 10?×?10 km grid cells covering the country. The primary factor driving the expanding population of jackals in northern B&H appears to be immigration of jackals from Croatia and Serbia.     

‘Arctic Crashes:’ Revisiting the Human-Animal Disequilibrium Model in a Time of Rapid Change

The paper introduces a new vision advanced by the recent project, Arctic People and Animal Crashes: Human, Climate and Habitat Agency in the Anthropocene (2014–2015) developed at the Smithsonian Institution. Unlike earlier top-down models of polar animal-climate-people connections that tied changes in Arctic species’ abundance and ranges to alternating warmer and cooler temperatures or high ice/low sea-ice regimes, rapid animal declines (‘crashes’) may be better approached at regional and local scales. This approach is close to Arctic peoples’ traditional vision that animals, like people, live in ‘tribes’ and that they ‘come and go’ according to their relations with the local human societies. As the Arctic changes rapidly and climate/sea-ice/ecotone boundaries shift, we see diverse responses by Arctic people and animals to environmental stressors. I examine recent data on the status of three northern mammal species – caribou/reindeer, Pacific walrus, and polar bear—during two decades of the ongoing Arctic warming. The emerging record may be best approached as a series of local human-animal disequilibria interpreted from different angles by population biologists, indigenous peoples, and anthropologists, rather than a top-down climate-induced ‘crash.’ Such new understanding implies the varying speed of change in the physical, animal, and human domains, which was not factored in the earlier models of climate–animal–people’s interactions.     

Potato cysteine proteinase inhibitor gene family: molecular cloning,characterisation and immunocytochemical localisation studies

Potato cysteine proteinase inhibitors (PCPIs) represent a distinct group of proteins as they show no homology to any other known cysteine proteinase inhibitor superfamilies, but they all belong to the Kunitz-type soybean trypsin inhibitor family. cDNA clones for five PCPIs have been isolated and sequenced. Amino acid substitutions occurring in the limited regions forming loops on the surface of these proteins suggest a further classification of PCPIs into three subgroups. Accumulation of PCPI was observed in vacuoles of stems after treatment with jasmonic acid (JA) using immunocytochemical localisation, implying that these inhibitors are part of a potato defence mechanism against insects and pathogens. Genomic DNA analysis show that PCPIs form a multigene family and suggest that their genes do not possess any introns.     

Leaf gas exchange and multiple enzymatic and non-enzymatic antioxidant strategies related to drought tolerance in two oil palm hybrids

Key message

The drought tolerance in young oil palm plants is related to greater efficiency in preventing oxidative damage by activating enzymatic and non-enzymatic antioxidant strategies simultaneously.

Abstract

Drought is a major environmental constraint limiting growth and yield of oil palm trees. In this study, two oil palm hybrids (BRS Manicoré and BRS C 2501) were grown in large containers and subjected to a water deficit during 57 days. Leaf gas exchange analysis was combined with an in-depth assessment of the antioxidant system over the drought imposition. Under drought, leaf water potential at predawn (Ψ _pd) decreased similarly in both hybrids. In parallel, there were decreases in the net CO₂ assimilation rate (A), chlorophyll concentrations and Rubisco total activity. Overall, these decreases were more pronounced in BRS C 2501 than in BRS Manicoré. BRS C 2501 plants triggered more markedly its enzymatic antioxidant system earlier (Ψ _pd = ?2.1 MPa) than did BRS Manicoré, but these responses were accompanied by higher concentrations of H₂O₂ and malondialdehyde in BRS C 2510 than in BRS Manicoré. With the progress of drought stress (Ψ _pd = ?2.9 MPa and below), BRS Manicoré was better able to cope with oxidative stress through a more robust antioxidant system. In addition, significant decreases in drought-induced NAD⁺-malate dehydrogenase activities were only observed in stressed BRS C 2501 plants. Regardless of watering regimes, the total carotenoid, ascorbate and glutathione concentrations were higher in BRS Manicoré than in BRS C 2501. In conclusion, BRS Manicoré is better able to tolerate drought than BRS C 2501 by triggering multiple antioxidant strategies involved both in reactive oxygen species scavenging and dissipation of excess energy and/or reducing equivalents particularly under severe drought stress.