Galvechelone lopezmartinezae gen. et sp. nov., a new cryptodiran turtle in the Lower Cretaceous of Europe

Abstract: The Spanish town of Galve (Teruel) is notable because of the abundance of Upper Jurassic and, especially, Lower Cretaceous vertebrates recorded there. Although most groups have been studied in detail, information on turtles is very limited even though the material is relatively abundant. So far, no turtle taxa have been identified at the generic level. The only Lower Cretaceous articulated specimen from Galve is analysed here. It is identified as a representative of Cryptodira, Galvechelone lopezmartinezae gen. et sp. nov. Galvechelone lopezmartinezae is determined as a taxon belonging to the node that groups the turtles traditionally assigned to ‘Macrobaenidae’ and ‘Sinemydidae’, and other taxa such as the members of Panchelonioidea. This node, very abundant in the Lower Cretaceous of Asia, and with a broad subsequent distribution, has recently been recognized in the Lower Cretaceous of Europe. The diversity of basal members of Eucryptodira in the European Late Jurassic (represented by Thalassemydidae, Plesiochelyidae and Eurysternidae) was high. Owing to a relative scarcity of well‐preserved early Cretaceous turtles from Europe, the knowledge of this group of reptiles is limited. The study of the new turtle from Galve, together with the recently described Hoyasemys jimenezi, and the recently completed review of the enigmatic Chitracephalus dumonii demonstrate that members of the cryptodiran node grouping ‘Macrobaenidae’, ‘Sinemydidae’ and Panchelonioidea were also very diverse in this period.     

Improving ability to identify malaria and correctly use chloroquine in children at household level in Nakonde District, Northern Province of Zambia

BACKGROUND: This study investigated causes of malaria and how cases were managed at household level, in order to improve the ability to identify malaria and ensure correct use of chloroquine. It was conducted in Nakonde District, Northern Province of Zambia, between 2000 and 2001. Nakonde district is in a hyperendemic malaria province, where Plasmodium falciparum is predominant. The district has a total population of 153, 548 people, the majority of whom are peasant farmers. The main aim of the post intervention survey was to establish the proportion of caretakers of children five years and below, who were able to identify simple and severe malaria and treat it correctly using chloroquine in the home. METHODS: A baseline survey was conducted in five wards divided into intervention and control.Intervention and control wards were compared. Village health motivators and vendors were identified and trained in three intervention wards, as a channel through which information on correct chloroquine dose could be transmitted. A total of 575 carers, who were 15 years old and above and had a child who had suffered from malaria 14 days before the survey commenced, were interviewed. The two control wards received no intervention. 345 caretakers were from the intervention wards, while 230 came from the control wards. Identification of malaria and correct use of anti-malarial drugs was assessed in terms of household diagnosis of malaria in children under five years, type and dose of anti-malarial drugs used, self medication and the source of these anti-malarials. RESULTS: The majority of respondents in the study were females (81%). Chloroquine was the most frequently used anti-malarial (48.5%) in both the intervention and control wards. There was no difference between the intervention and control wards at pre-intervention (P = 0.266 and P = 0.956), in the way mothers and other caretakers identified simple and severe malaria. At baseline, knowledge on correct chloroquine dosage in the under five children was comparable between intervention and control wards. Post-intervention revealed that mothers and other caretakers were 32% and 51%, respectively, more likely to identify simple and severe malaria. There was a 60% increase on correct chloroquine dosage in all age groups among carers living in post-intervention wards. CONCLUSION: Compliance with standard therapeutic doses and correct identification of malaria was poorest in control wards, where no motivators and vendors were trained.     

Membrane phase behavior during cooling of stallion sperm and its correlation with freezability

Stallion sperm exhibits great male-to-male variability in survival after cryopreservation. In this study, we have investigated if differences in sperm freezability can be attributed to membrane phase and permeability properties. Fourier transform infrared spectroscopy (FTIR) was used to determine supra and subzero membrane phase transitions and characteristic subzero membrane hydraulic permeability parameters. Sperm was obtained from stallions that show differences in sperm viability after cryopreservation. Stallion sperm undergoes a broad and gradual phase transition at suprazero temperatures, from 30-10°C, whereas freezing-induced dehydration of the cells causes a more severe phase transition to a highly ordered gel phase. Sperm from individual stallions showed significant differences in post-thaw progressive motility, percentages of sperm with abnormal cell morphology, and chromatin stability. The biophysical membrane properties evaluated in this study, however, did not show clear differences amongst stallions with differences in sperm freezability. Cyclodextrin treatment to remove cholesterol from the cellular membranes increased the cooperativity of the suprazero phase transition, but had little effects on the subzero membrane phase behavior. In contrast, freezing of sperm in the presence of protective agents decreased the rate of membrane dehydration and increased the total extent of dehydration. Cryoprotective agents such as glycerol decrease the amount of energy needed to transport water across cellular membranes during freezing.     

Membrane hydraulic permeability changes during cooling of mammalian cells

In order to predict optimal cooling rates for cryopreservation of cells, the cell-specific membrane hydraulic permeability and corresponding activation energy for water transport need to be experimentally determined. These parameters should preferably be determined at subzero temperatures in the presence of ice. There is, however, a lack of methods to study membrane properties of cells in the presence of ice. We have used Fourier transform infrared spectroscopy to study freezing-induced membrane dehydration of mouse embryonic fibroblast (3T3) cells and derived the subzero membrane hydraulic permeability and the activation energy for water transport from these data. Coulter counter measurements were used to determine the suprazero membrane hydraulic permeability parameters from cellular volume changes of cells exposed to osmotic stress. The activation energy for water transport in the ice phase is about three fold greater compared to that at suprazero temperatures. The membrane hydraulic permeability at 0 °C that was extrapolated from suprazero measurements is about five fold greater compared to that extrapolated from subzero measurements. This difference is likely due to a freezing-induced dehydration of the bound water around the phospholipid head groups. Using Fourier transform infrared spectroscopy, two distinct water transport processes, that of free and membrane bound water, can be identified during freezing with distinct activation energies. Dimethylsulfoxide, a widely used cryoprotective agent, did not prevent freezing-induced membrane dehydration but decreased the activation energy for water transport.     

SH3 ligands in the dopamine D3 receptor

It has recently been observed that G protein-coupled receptors (GPCRs) can interact with SH3 domains through polyproline motifs. These interactions appear to be involved in receptor internalization and MAPK signalling. Here we report that the third cytoplasmic loop of the dopamine D3 receptor can interact in vitro with the adaptor protein Grb2. While the amino- and carboxy-terminal SH3 domains of Grb2 separately did not interact with the D3 receptor loop, the interaction is at least partially maintained with a Grb2 mutant for the amino-terminal SH3 domain, but disrupted for a Grb2 mutant with a nonfunctional carboxy-terminal SH3 domain. The data indicate the need of structural integrity of the entire Grb2 protein for the interaction and dominant role of the carboxy-terminal SH3 domain in the interaction. Disruption of the PXXP motifs in the D3 receptor did not affect the interaction with Grb2. These results indicate that GPCRs may contain SH3 ligands that do not contain the postulated minimal consensus sequence PXXP.     

Freezing and desiccation tolerance in the moss Physcomitrella patens: An in situ Fourier transform infrared spectroscopic study

In situ Fourier transform infrared spectroscopy (FTIR) was used in order to obtain more insights in the underlying protective mechanisms upon freezing and drying of ABA-treated tissues of the moss Physcomitrella patens. The effects of different treatments on the membrane phase behaviour, glassy state, and overall protein secondary structure were studied. We found that growth on ABA resulted in the accumulation of sucrose: up to 22% of the tissue on a dry weight basis, compared to only 3.7% in non-ABA-treated tissues. Sucrose functions as a protectant during freezing and drying, but accumulation of sucrose alone is not sufficient for survival. ABA-treated tissue survives a freeze–thaw cycle down to −80 °C only after addition of an additional cryoprotectant (DMSO). Survival correlates with preservation of membrane phase behaviour. We found that ABA-treated P. patens can survive slow but not rapid drying down to water contents as low as 0.02 g H₂O per g DW. Rapidly and slowly dried ABA-treated tissues were found to have similar sugar compositions and glass transition temperatures. The average strength of hydrogen bonding in the cytoplasmic glassy matrix, however, was found to be increased upon slow drying. In addition, slowly dried tissues were found to have a higher relative proportion of α-helical structures compared to rapidly dried tissues.     

Comparison of tetrachromic VOF stain to other histochemical staining techniques for characterizing stromal soft and hard tissue components

The components of hard tissues including dentin, enamel, cementum, bone and other calcified deposits, and mature and immature collagen pose problems for identification in routine hematoxylin and eosin (H & E) stained sections. Use of combinations of stains can demonstrate the components of hard tissues and soft tissues distinctly. We assessed the efficacy of the Verde Luz-orange G-acid fuchsin (VOF) stain for differentiating hard and soft connective tissues and compared results with other histochemical staining techniques. Eighty tissue sections comprising developing tooth (30), ossifying fibroma (30) and miscellaneous pathologies (20) expected to contain varying types of calcified tissues were stained with H & E, VOF, and Masson's trichrome (MT). In developing tooth, VOF demonstrated better differentiation of hard tissues, while it was comparable to MT for ossifying fibroma and miscellaneous pathologies. The intensity of staining was greater with VOF than with the other stains studied. VOF stains hard tissue components distinctly and gives good contrast with the surrounding connective tissue. VOF is comparable to MT, but has added advantages including single step staining, rapid and easy procedures, and it distinguishes the maturity of the tissues.