Mass spectrometry of intact V-type ATPases reveals bound lipids and the effects of nucleotide binding

The ability of electrospray to propel large viruses into a mass spectrometer is established and is rationalized by analogy to the atmospheric transmission of the common cold. Much less clear is the fate of membrane-embedded molecular machines in the gas phase. Here we show that rotary adenosine triphosphatases (ATPases)/synthases from Thermus thermophilus and Enterococcus hirae can be maintained intact with membrane and soluble subunit interactions preserved in vacuum. Mass spectra reveal subunit stoichiometries and the identity of tightly bound lipids within the membrane rotors. Moreover, subcomplexes formed in solution and gas phases reveal the regulatory effects of nucleotide binding on both ATP hydrolysis and proton translocation. Consequently, we can link specific lipid and nucleotide binding with distinct regulatory roles.     

A case study of FD and BN phytoplasma variability in Croatia: multigene sequence analysis approach

European Journal of Plant Pathology - Uncultivable bacteria from the genus ‘Candidatus Phytoplasma’ are associated with grapevine yellows (GY) diseases worldwide. In Euro-Mediterranean...     

Physiological Indices of Maricultured Mussel Mytilus galloprovincialis Lamarck, 1819 in Istria,Croatia: Seasonal and Transplantation Effect

Transplantation of mussels to new aquaculture sites is currently being undertaken in Istria (Croatia) to increase production, minimize potential seasonal urban contamination, and secure safer seafood products. The purpose of this study was to determine the effects of season and transplantation on physiological indices (condition index and meat yield) of mussels, Mytilus galloprovincialis. Mussels were obtained from five aquaculture areas in Istria (central Lim Bay, Ra?a, Budava, Vabriga, and Pomer) and moved to a reference site in inner Lim Bay from April to July. Results showed that both season and transplantation affected physiological indices of mussels. Higher physiological indices were found in cultivated mussels from all areas in summer compared to spring, except in mussels from Vabriga and Pomer. In addition, higher physiological indices were found in mussels transplanted from central Lim Bay to the reference site in inner Lim Bay. Transplantation negatively affected physiological indices of mussels from Vabriga and Pomer, with no change in mussels from Ra?a and Budava. In conclusion, mussels from all areas exhibit satisfactory commercial results (≥15%) during the peak summer harvesting season. For most transplanted mussels, transplantation itself represents additional stress, bringing into focus adaptation processes, stock genetics, and favorable ecological conditions.     

Crystal structures of human cytochrome P450 3A4 bound to metyrapone and progesterone

Cytochromes P450 (P450s) metabolize a wide range of endogenous compounds and xenobiotics, such as pollutants, environmental compounds, and drug molecules. The microsomal, membrane-associated, P450 isoforms CYP3A4, CYP2D6, CYP2C9, CYP2C19, CYP2E1, and CYP1A2 are responsible for the oxidative metabolism of more than 90% of marketed drugs. Cytochrome P450 3A4 (CYP3A4) metabolizes more drug molecules than all other isoforms combined. Here we report three crystal structures of CYP3A4: unliganded, bound to the inhibitor metyrapone, and bound to the substrate progesterone. The structures revealed a surprisingly small active site, with little conformational change associated with the binding of either compound. An unexpected peripheral binding site is identified, located above a phenylalanine cluster, which may be involved in the initial recognition of substrates or allosteric effectors.     

Comparison of different methods for Citrus tristeza virus detection in Satsuma mandarins

Journal of Plant Diseases and Protection - Citrus tristeza virus (CTV) infection in 13 Satsuma (Citrus unshiu (Mak.) Marc.) symptomless clones was investigated by different diagnostic methods,...     

Assessment of heavy metal pollution in surface sediments of the Montenegrin coast: a 10-year review

Purpose

Heavy metals are among the most common environmental pollutants, which can be introduced into coastal areas from natural and anthropogenic sources, and thereby possibly impact marine organisms and human population. Therefore, the aim of this study was to evaluate the pollution level of Montenegrin coastal sediments by determining the concentrations of 10 metals and metalloids (Fe, Mn, Zn, Cu, Ni, Pb, Cr, Cd, As, and Hg) during one whole decade.

Materials and methods

Sediment samples were collected from 11 sites along the Montenegrin coast during the 2005–2016 exposure to different levels and sources of anthropogenic impact. The extent of pollution was estimated by determining total element concentrations in the sediment. Mineralized samples were analyzed for Cu, Ni, Fe, Mn, Cr, As, Pb, Zn, Cd, and Hg. Pollution status was evaluated using the contamination factor, pollution load index, and geo-accumulation index, as well as statistical methods, such as Pearson correlation coefficient (r) and cluster analysis (CA).

Results and discussion

This study showed that concentrations of individual metals at some locations were extremely high. The metal concentrations (in mg kg^?1) ranged as follows: Fe 1995–45,498; Mn 135–1139; Zn 10–1596; Cu 3.8–2719; Ni 2.94–267; Pb 0.1–755; Cr 2.5–369; Cd 0.1–5.4; As 0.1–39.1; and Hg 0.01–14.2. The calculated concentration factor and pollution load index indicates enrichment by either natural processes or anthropogenic influences. The geo-accumulation index value (Igeo) showed that one location was strongly or extremely polluted (3.78?<?Igeo ≤?6.15) with Hg in all investigated years, while extreme Igeo values for four bioactive elements, Pb, Cd, Cu, and Zn, were found in only a few single samples.

Conclusions

On the basis of the obtained values, it can be concluded that generally higher metal contents were distributed in Boka Kotorska Bay sites, although some extreme values were also recorded at the locations outside of the Bay. Geo-accumulation index and pollution load index showed that the metal levels were high enough to pose risk to the ecosystem.

     

East Adriatic—a reservoir region of severe <Emphasis Type="Italic">Citrus tristeza virus</Emphasis> strains

Citrus tristeza virus (CTV) represents one of the major threats to citrus production worldwide. In the East Adriatic region, CTV symptoms are mostly absent due to traditional citrus grafting on trifoliate orange (Poncirus trifoliata), a CTV-tolerant rootstock. Therefore, the virus has been continuously spreading by the propagation of infected material. The genetic variability of CTV was studied on nineteen citrus samples, collected from orchards in the coastal region of Croatia, Montenegro and Albania, that previously tested positive by ELISA and immunocapture RT-PCR. Single-strand conformation polymorphism of the amplified coat protein gene demonstrated the presence of different CTV variants in each amplicon, while sequence analysis of cloned CP gene variants confirmed their clustering into six out of the seven phylogenetic groups so far delineated. Four of these groups include sequences of severe quick decline, seedling yellows and stem-pitting (SP) isolates, thought to be found only rarely in the Mediterranean region. Regardless of the lack of symptoms in the field, CTV isolates from the East Adriatic displayed high genetic variability and pathogenic potential, additionally confirmed by biological characterisation. The high percentage of mixed infections suggest the potential for further diversification and a greater risk of severe variants spreading into new areas.