Jumping into the grids: mapping biodiversity hotspots in groundwater habitat types across Europe

Biodiversity hotspots are routinely identified by grid-based analyses, despite grids encompassing different habitats, thus hindering the potential to assess which habitat type accounts for the conservation priority assigned to a grid. In this study, we aimed at identifying the main hotspots for the conservation of the European stygobitic Crustacea Copepoda Harpacticoida at the groundwater habitat scale. A multi-metric approach was used, based on six biodiversity indicators: species richness, endemicity, evolutionary origin, phylogenetic rarity, taxonomic distinctness, habitat specificity. The Hot Spot Analysis, based on the statistics Getis-Ord Gi*, was used to compare the local to the global average values of each indicator to identify hotspots of conservation. The operational units used to perform the analyses were the groundwater habitat types, in order to gather all the possible patterns of spatial occupancy in terms of habitat variability. Eight biodiversity hotspots of stygobitic Crustacea Harpacticoida were highlighted: 1) the Pyrenees (Spain and France), 2) the Jura Massif (France), 3) the Alpine arc (France, Switzerland and Italy) embracing southward the River Po alluvial plain and the Slovenian External Dinarides, 4) the Central Apennines (Italy), 5) the Carpathian and Balkan mountains in Romania and at the boundary between western Bulgaria and north-west Macedonia, 6) the Dinaric Alps (from Croatia to Albania), 7) the Sardinia Island, 8) an area in central-northern Europe embracing Denmark, the Netherlands and Germany. The hotspots showed a clear spatial distribution in southern Europe where they were distributed predominantly south to the 45th parallel, in line to what reiteratively observed in previous studies. Many hotspots embraced more than one habitat type. The adoption of discrete groundwater habitat types as working spatial units rather than grids provided a higher resolution of where the stygobitic harpacticoid species effectively live, with the possibility of intervening more precisely to preserve them and their habitats.     

Dry soil determines the pseudoviviparous reproduction in Comanthera nivea (Eriocaulaceae) in the Campos Rupestres in south-eastern Brazil

Pseudovivipary is an asexual reproduction strategy correlated with extreme environments. Comanthera nivea occurs in habitats with low water retention. This study investigated the effect of soil moisture availability on C. nivea pseudoviviparous reproduction and flowering. We established four permanent plots (1 × 1 m), two in a shaded area, in which we marked 15 rosettes in each plot, and two in a full-sun area, in which we marked 10 rosettes in each plot. We made monthly observations from August 2016 to January 2017, to quantify the number of flower heads and of pseudoviviparous ramets per rosette, and measured soil moisture. Our results showed a high correlation between soil moisture and flowering. Flowering in C. nivea occurs in periods of increased soil moisture, whereas pseudoviviparous reproduction occurs in the driest period. The advantages of a pseudoviviparous canopy-forming strategy in habitats with scarcity of water in the soil are discussed.     

Synthesis and crystallographic analysis of new sulfonamides incorporating NO-donating moieties with potent antiglaucoma action

Several aromatic/heterocyclic sulfonamide scaffolds have been used to synthesize compounds incorporating NO-donating moieties of the nitrate ester type, which have been investigated for the inhibition of five physiologically relevant human carbonic anhydrase (hCA, EC 4.2.1.1) isoforms: hCA I (offtarget), II, IV and XII (antiglaucoma targets) and IX (antitumor target). Some of the new compounds showed effective in vitro inhibition of the target isoforms involved in glaucoma, and the X-ray crystal structure of one of them revealed factors associated with the marked inhibitory activity. In an animal model of ocular hypertension, one of the new compounds was twice more effective than dorzolamide in reducing elevated intraocular pressure characteristic of this disease, anticipating their potential for the treatment of glaucoma.     

A revision of the South African Chaetocnema gahani speciesgroup,with descriptions of four new flea beetle species (Coleoptera: Chrysomelidae)

The Chaetocnema gahani species-group from Southern Africa is herein analyzed and revised. It includes C. gahani Jacoby 1897, C. brincki (Bechyné 1959), C. capeneri n. sp., C. danielssoni n. sp., C. sudafricana n. sp., and C. tuckeri n. sp. A key to all the species is presented. Line drawings of male and female genitalia and scanning electron micrographs of six diagnostic morphological characters are also included, along with ecological and zoogeographical data. Finally, discriminant analyses using the six morphological characters supports the close affinity of the six species within the C. gahani group.     

N-Heteroarylmethyl-5-hydroxy-1,2,5,6-tetrahydropyridine-3-carboxylic acid a novel scaffold for the design of uncompetitive α-glucosidase inhibitors

The enzyme α-glucosidase has attracted interest owing to its involvement in the digestive process of carbohydrate, its role in intracellular glycoprotein trafficking, tumorigenesis and viral infection. In this study, several members of a new family of N-heteroarylmethyl substituted azasugars were synthesized and evaluated as α-glucosidase inhibitors. We systematically investigated the effect of different N-substituents as well as the role of hydroxyl and carboxylate moieties on the piperidine ring. The compounds N-heteroarylmethyl-5-hydroxy-1,2,5,6-tetrahydropyridine-3-carboxylic acid emerged as potent α-glucosidase inhibitors. Unlike Acarbose and other clinically relevant α-glucosidase inhibitors, these compounds act through a reversible uncompetitive mechanism of inhibition which make them attractive candidates for drug development.     

Taxodioxylon gypsaceum (Göppert) Kräusel,legno fossile rinvenuto nel miocene dell'Italia centrale

Abstract

Taxodioxylon gypsaceum (Göppert) Kräusel, wood fossil discovered in the central italian miocene.—A sample of silicified wood fossil has been discovered in the miocenic formations of the Castellaro mountain in the neighbourhood of Pesaro a city in Central Italy. An anatomical study has made it possible to accept that the species is Taxodioxylon gypsaceum, which resembles the actual Sequoia sempervirens for its woody structure, conservative endemism of a coastal region in California. The fossil species that is known for its numerous tertiary deposits in the Northern, Central and Eastern Europe, is now indicated for the first time in Italy; the mount Castellaro station results to be the more south among those in Europe.

Various paleobotanical data concerning traces of leaves, fruits and seeds gathered in localities near to the deposit and in the region complies with the discovery of Taxodioxylon gypsaceum because of the presence of varions species of Sequoia and Taxodium and in particular of the Sequoia langsdorfii leaves which is considered as the ancient form of the Sequoia sempervirens.     

Phosphoinositide-dependent protein kinase 1, a sensor of protein conformation

Phosphoinositide-dependent protein kinase 1 (PDK1) is a protein kinase that phosphorylates and activates several other protein kinases from the AGC group (which includes PKA, PKG and PKC), to which PDK1 also belongs. Recent data suggests that PDK1 specificity is achieved by regulation of its interaction with substrates and supports a rather simple model explaining how PDK1 interacts with different substrates. The data further suggests that PDK1 interacts with its substrates when they are in a particular conformation (inactive). PDK1 has the ability to recognize, interact with and phosphorylate specific substrate conformations and thus sets PDK1 at the centre of a protein conformation sensor mechanism. The PDK1-substrate interaction model describes, at a molecular level, the mechanism used by PDK1 to sense the conformation of its substrates.     

Genetic relationship of Sinorhizobium meliloti and Sinorhizobium medicae strains isolated from Caucasian region

Sinorhizobium meliloti and Sinorhizobium medicae are two closely related species of the genus Sinorhizobium showing a similar host range, nodulating leguminous species of the genera Medicago, Melilotus and Trigonella, but their phylogenic relationship has not been elucidated yet. In this paper we report the application of three different molecular markers, (i) RFLP of nodD genes, (ii) 16S-23S rDNA intergenic gene spacer fingerprinting and (iii) amplification fragment length polymorphism to S. meliloti and S. medicae strains isolated from the Caucasian area, which is the region of origin of the host plant Medicago. The analysis of data could suggest the origin of S. medicae strains from an ancestral S. meliloti population.     

Postnatal development of subterranean habits in tuco-tucos <Emphasis Type="Italic">Ctenomys talarum</Emphasis> (Rodentia,Caviomorpha, Ctenomyidae)

Postnatal development of subterranean habits was investigated in Los Talas’ tuco-tuco Ctenomys talarum, a subterranean caviomorph rodent endemic from South America. Since in this species, some key morpho-functional traits related to scratch-digging behaviour—a form of underground progression—are already present during early ontogeny and develop progressively, we predicted that this behaviour expresses early during postanatal development and its performance enhances gradually from pups to adults. The process of acquisition of different behaviours associated to the construction of a burrow system was recorded in 11 individuals, each one coming from different litters, inside a terrarium filled with natural soil. We found that scratch-digging and burrowing behaviours expressed early during postnatal development, particularly, during lactancy. The digging of a “true burrow” clearly preceded the dispersal age, with a high inter-individual variability, from 18 (lactancy) to 47 (post-weaning) postnatal days. Pups could lose the soil using their foreclaws and remove the accumulated substrate using their hindfeet as adults do. During lactancy individuals could construct a simple burrow to shelter, and first burrow construction occurred in the absence of either a burrowing demonstrator or an early subterranean environment (a natal burrow). However, certain features of the complex burrow system that characterize this species, such as lateral branches and nest chamber, just appeared after weaning. The time elapsed until animals started to dig and the time dedicated to underground activities varied with age, decreasing and increasing, respectively. In sum, our results show that—in C. talarum—immature digging behaviour gets expressed early during ontogeny, and develops progressively. The role of the early ability to build its own burrow and its possible function influencing the development of musculoskeletal traits and on efficiency for such conduct is discussed.     

Characterization of volatile organic compounds emitted by kiwifruit plants infected with <Emphasis Type="Italic">Pseudomonas syringae</Emphasis> pv. <Emphasis Type="Italic">actinidiae</Emphasis> and their effects on host defences

Key message

Specific VOC emissions from infected plants allow their recognition and elicit defence responses in neighboring plants, which are, however, insufficient to induce resistance.

Abstract

A wide range of volatile organic compounds (VOCs) is released during plant–pathogen interactions both by the pathogens and the hosts. Some of these VOCs are specific for the different diseases and are known to play a role in the pathogenicity or in plant defence responses. Besides, disease-specific VOCs may serve as markers for diagnostic protocols, which allow a non-destructive and rapid screening of bulk samples of plant material. This work aimed to verify the feasibility of a VOC-based diagnosis and to investigate the possible biological role of VOCs released during the plant–pathogen interactions. The volatile emissions from Pseudomonas syringae pv. actinidiae in axenic cultures and from inoculated in vitro kiwifruit plants were characterized by gas chromatography–mass spectrometry (GC–MS) and proton transfer reaction–time-of-flight-mass spectrometry (PTR–ToF-MS). By GC–MS, several putative biochemical markers, such as 1-undecene, were identified. PTR–ToF-MS resulted highly effective in screening the plant material for latent infections. To develop a more user-friendly, portable and less expensive diagnosis system, two different electronic nose models were tested for the early diagnosis of P. syringae pv. actinidiae in asymptomatic plant material. Our experiments demonstrated the feasibility of the electronic nose-based screening of infected plant material. Concerning the biological role of the VOCs released during the plant–pathogen interactions, the exposure of healthy plants to VOCs from infected ones influences the plant growth and induces the stimulation of protective responses. However, after the infection, P. syringae pv. actinidiae is able to selectively inactivate the induced plant defences.