Clostridium carboxidivorans Strain P7T Recombinant Formate Dehydrogenase Catalyzes Reduction of CO2 to Formate

Recombinant formate dehydrogenase from the acetogen Clostridium carboxidivorans strain P7^T, expressed in Escherichia coli, shows particular activity towards NADH-dependent carbon dioxide reduction to formate due to the relative binding affinities of the substrates and products. The enzyme retains activity over 2 days at 4°C under oxic conditions.     

Feeding in the frequency domain: coarser‐grained environments increase consumer sensitivity to resource variability,covariance and phase

Theory predicts that resource variability hinders consumer performance. How this effect depends on the temporal structure of resource fluctuations encountered by individuals remains poorly understood. Combining modelling and growth experiments with Daphnia magna, we decompose the complexity of resource fluctuations and test the effect of resource variance, supply peak timing (i.e. phase) and co‐limiting resource covariance along a gradient from high to low frequencies reflecting fine‐ to coarse‐grained environments. Our results show that resource storage can buffer growth at high frequencies, but yields a sensitivity of growth to resource peak timing at lower ones. When two resources covary, negative covariance causes stronger growth depression at low frequencies. However, negative covariance might be beneficial at intermediate frequencies, an effect that can be explained by digestive acclimation. Our study provides a mechanistic basis for understanding how alterations of the environmental grain size affect consumers experiencing variable nutritional quality in nature.     

Biology and behavior of Metaphycus angustifrons Compere (Hymenoptera: Encyrtidae), a newly discovered parasitoid of soft scale insects (Hemiptera: Coccidae) in California

Metaphycus angustifrons Compere has recently been found to be the most abundant parasitoid of brown soft scale, Coccus hesperidum L., in southern California. In laboratory experiments we examined several biological parameters of this species. M. angustifrons both oviposits and host feeds in brown soft scale and is a facultatively gregarious endoparasitoid of this soft scale insect. In contrast with other Metaphycus spp., M. angustifrons is a koinobiont parasitoid, allowing its host to grow up to 40% beyond its size at parasitism. Despite its high abundance on brown soft scale in the field, in the laboratory, high rates of parasitoid egg encapsulation are observed; about half of parasitized hosts failed to issue parasitoids. Furthermore, host scales that encapsulated parasitoids eggs showed significant reduction in development. Increased scale size at oviposition influences the size of emerging females but not the size of males. Female M. angustifrons are synovigenic. They emerge from their hosts without mature eggs and begin maturing eggs after they are provided a carbohydrate source. Carbohydrates prolong the life span of both female and male M. angustifrons. The size of female wasps influences egg load but not longevity. Finally, based on laboratory observations, M. angustifrons uses citricola scale almost exclusively for host feeding and not for oviposition. These results suggest that the role of this species in citricola scale’s decline in southern California in the 1950s–1960s was negligible.     

Expression of tissue remodelling,inflammation- and angiogenesis-related factors after eccentric exercise in humans

Molecular Biology Reports - Eccentric exercise has been extensively used as a model to study the contraction-induced muscle damage and its consequent processes. This study aimed at examining...     

Molecular Diversity and Assessment of Biological Characteristics of Greek Colletotrichum lindemuthianum Populations

Colletotrichum lindemuthianum  isolates collected in Greece were characterized by the temperature effect on their biological characteristics (mycelial growth, sporulation and spore germinability) and by molecular diversity revealed by RAM and ERIC–BOX PCR analysis. The temperature effect on the assessed biological characteristics resulted in a similar classification according to the origin and virulence patterns of isolates. Colletotrichum lindemuthianum isolates originating from the areas of Nevrokopi and Vrodou showed better adaptation at the lower temperatures exposure (12 and 18°C) compared to isolates originating from the Municipality of Hrisoupolis, which showed better adaptation at the highest temperature tested (24°C). Molecular diversity was detected using RAM and ERIC–BOX PCR primers. Both methods revealed, in a similar way ( r  = 0.58, P = 0.05), two main clusters of isolates, in agreement with previous findings using RAPD and RFLP analysis. The majority of the tested isolates were grouped in the same main cluster (29 out of 35 Greek isolates for both methods) underlying high levels of genotypic similarities between Greek populations of C. lindemuthianum . This study, an extension of previous research, provides further information on population diversity of C. lindemuthianum required for developing more efficient control strategies of bean anthracnose disease.     

Drug Resistance in Natural Isolates of Leishmania donovani s.l. Promastigotes Is Dependent of Pgp170 Expression

Resistance of pathogens to drugs is a growing concern regarding many diseases. Parasites like Leishmania, Plasmodium and Entamoeba histolytica; and neoplastic cells, present the multidrug-resistant phenotype rendering chemotherapy ineffective. The acquired resistance of Leishmania to antimony has generated intense research on the mechanisms involved but the question has not yet been resolved. To test the hypothesis that drug efflux in Leishmania, as measured by flow cytometry using the fluorescent dye Rhodamine-123, is largely dependent on the number of efflux pumps an isolate can express, the amount of Pgp 170 molecules was assessed in ten field isolates (5 “resistant” and 5 “susceptible”) using: Western Blotting, Confocal and Transmission Electron Microscopy, and proteomics. Their survival after exposure to three antileishmanial drugs, in vitro, was evaluated and clinical data were compared to the in vitro results. All isolates were resistant to Glucantime but susceptible to Miltefosine, whilst Amphotericin B was more effective on the “susceptible” isolates. The MDR gene, expressing the transmembrane efflux pump Pgp 170, appears to play a key role in the phenomenon of drug resistance. When “susceptible” versus “resistant” parasites were compared, it was shown that the higher the number of Pgp 170 molecules the higher the Rhodamine-123 efflux from the parasite body and, when exposed to the drug, the number of efflux pumps increased. However, the rate of this increase was not linear and it is possible that there is a maximum number of Pgp 170 molecules an isolate can express. Nevertheless, the phenomenon is a complex one and other factors and proteins are involved in which the HSP-70 group proteins, detected in the “resistant” isolates, may play a significant role.     

Segmental and restricted localization pattern of Fras1 in the developing meningeal basement membrane in mouse

The Fras1/Frem family of extracellular matrix proteins consists of Fras1 and its structurally related proteins, Frem1 (Fras1-related extracellular matrix protein 1), Frem2 and Frem3. These are co-localized in embryonic epithelial basement membranes (BMs), where they contribute to epithelial–mesenchymal adhesion. Although Fras1 localization pattern in epithelial BMs has been well defined, it has not yet been comprehensively studied in the central nervous system. Here, we demonstrate the immunohistochemical profile of Fras1 in the developing mouse brain and reveal an exclusively meningeal BM protein deposition. Interestingly, Fras1 displays a segmental localization pattern, which is restricted to certain regions of the meningeal BM. Frem2 protein displays a similar localization pattern, while Frem3 is rather uniformly distributed throughout the meningeal BM. Fras1 and Frem2 proteins are detected in regions of the BM that underlie organizing centers, such as the roof plate (RP) of diencephalon, midbrain and hindbrain, and the RP-derived structures of telencephalon (choroid plexus and hem). Organizing centers exert their activity via the production of bioactive molecules, which are potential Fras1 ligands. The restricted pattern of Fras1 and Frem2 proteins indicates a molecular compartmentalization of the meningeal BM that could reflect, yet unspecified, functional and structural differences.