Betaine accumulation and betaine-aldehyde dehydrogenase in spinach leaves

Spinach leaf discs accumulated betaine when exposed to a mannitol solution of −20 bars. The accumulation was 12 micromoles per gram original fresh weight in a 24-hour period.     

Congenital amusia persists in the developing brain after daily music listening

Congenital amusia is a neurodevelopmental disorder that affects about 3% of the adult population. Adults experiencing this musical disorder in the absence of macroscopically visible brain injury are described as cases of congenital amusia under the assumption that the musical deficits have been present from birth. Here, we show that this disorder can be expressed in the developing brain. We found that (10-13 year-old) children exhibit a marked deficit in the detection of fine-grained pitch differences in both musical and acoustical context in comparison to their normally developing peers comparable in age and general intelligence. This behavioral deficit could be traced down to their abnormal P300 brain responses to the detection of subtle pitch changes. The altered pattern of electrical activity does not seem to arise from an anomalous functioning of the auditory cortex, because all early components of the brain potentials, the N100, the MMN, and the P200 appear normal. Rather, the brain and behavioral measures point to disrupted information propagation from the auditory cortex to other cortical regions. Furthermore, the behavioral and neural manifestations of the disorder remained unchanged after 4 weeks of daily musical listening. These results show that congenital amusia can be detected in childhood despite regular musical exposure and normal intellectual functioning.     

Phosphatidylserine delivery to endoplasmic reticulum-derived vesicles of plant cells depends on two biosynthetic pathways

Vesicles formed from endoplasmic reticulum (ER) by a cell-free system of leek cells (Allium porrum) are enriched in phosphatidylserine (PS), especially species containing very long chain fatty acids (VLCFA, at least 20 carbon atoms). In plant cells, PS is formed either by PS synthase or the serine exchange enzyme, although it is not known which pathway(s) contribute(s) to PS delivery in the ER-derived vesicles (EV), nor to what extent this occurs. Taking advantage of a cell-free system, we have shown that PS enrichment originates mainly from the serine exchange enzyme which is the only pathway that synthesizes the VLCFA-PS species. On the other hand, both enzymes synthesize PS with long chain fatty acids (up to 18 carbon atoms), but these species are given to the EV by PS synthase.     

A new subfamily of high molecular mass CDC2-related kinases with PITAI/VRE motifs

Kinases of the CDC2 family play a key role in cell cycle regulation and gene expression. In the present work, we identified sea urchin and human cDNAs encoding homologues of a high molecular mass CDC2-like kinase (designated CDC2L5) sharing respectively a PITAVRE and PITAIRE motif. The human cDNA encodes the full-length amino acid sequence of the cholinesterase-related cell division controller (CHED) kinase, a previously published partial coding sequence. CDC2L5 overexpressed in mammalian cells is an approximately 170-kDa nuclear protein. The mRNA is present during the sea urchin early embryogenesis and is ubiquitously expressed in human tissues.     

Interfacial enzymology of parvovirus phospholipases A2

The capsid of parvoviruses proteins were recently shown to contain secreted phospholipase A(2) (sPLA(2))-like activity that is required during host cell entry. Parvoviral PLA(2) domains have little sequence identity with sPLA(2)s and lack disulfide bonds. In the present study, after bacterial expression and purification, the biochemical characterizations of these first PLA(2)s identified in viruses have been investigated, and a comparison has been made with other known PLA(2)s. The specific activities of three viral PLA(2)s differed by 3 orders of magnitude, with porcine parvovirus PLA(2) displaying a specific activity similar to that of the most active sPLA(2)s (e.g. human group IIA) and the human AAV2 and B19 parvoviral enzymes displaying approximately 10(3) lower specific activities (similar to human sPLA(2) groups IIE and XIIA). These differences were not caused by weaker Ca(2+) or interfacial binding. The specific activities of the viral PLA(2)s on zwitterionic or anionic phospholipid vesicles were comparable. The viral PLA(2)s did not display a preference for unsaturated versus saturated sn-2 fatty acyl chains and hydrolyzed all major classes of glycero-phospholipids except phosphatidylinositol. Incubation of mammalian cells with porcine parvovirus PLA(2) led to the release of arachidonic acid into the culture medium. Interestingly, among nine previously known sPLA(2) inhibitors, only a subset showed inhibition of the viral PLA(2)s and with weak potency, indicating that the active sites of these new enzymes are structurally distinct from those of sPLA(2)s. Based on these distinct enzymatic and structural properties, we propose to classify the parvovirus PLA(2)s within the PLA(2) superfamily as group XIII enzymes.     

A cost of Wolbachia-induced sex reversal and female-biased sex ratios: decrease in female fertility after sperm depletion in a terrestrial isopod

A number of parasites are vertically transmitted to new host generations via female eggs. In such cases, host reproduction is an intimate component of parasite fitness and no cost of the infection on host reproduction is expected to evolve. A number of these parasites distort host sex ratios towards females, thereby increasing either parasite fitness or the proportion of the host that transmit the parasite. In terrestrial isopods (woodlice), Wolbachia bacteria are responsible for sex reversion and female-biased sex ratios, changing genetic males into functional neo-females. Although sex ratio distortion is a powerful means for parasites to increase in frequency in host populations, it also has potential consequences on host biology, which may, in turn, have consequences for parasite prevalence. We used the woodlouse Armadillidium vulgare to test whether the interaction between Wolbachia infection and the resulting excess of females would limit female fertility through the reduction in sperm number that they receive from males. We showed that multiple male mating induces sperm depletion, and that this sperm depletion affects fertility only in infected females. This decrease in fertility, associated with male mate choice, may limit the spread of Wolbachia infections in host populations.     

Intestinal parasitoses among Wayampi Indians from French Guiana

Intestinal parasitism and its epidemiological characteristics were studied in an isolated Amerindian population from Upper Oyapock (French Guiana) that has retained its traditional social and cultural specificities. This population consisted of 138 Wayampi Indians, 68 adults and 70 children (below the age of 15 years), with a sex ratio (M/F) of 0.86, spread over the four villages of the community of Trois Sauts, corresponding to more than two thirds of the population recorded as inhabiting the sector in the last census (375 inhabitants). Fecal examination combined the direct examination of fresh feces with the quantitative techniques of Kato-Katz method, Baermann and MIF staining. Overall, 92% of the subjects were found to have intestinal parasites, 85% if only direct examination of fresh stools was taken into account. Fourteen species of human parasite were identified: seven protozoa and seven helminths. We observed in particular 1) a high frequency of hookworm infection due to Necator americanus. Over 50% of subjects were affected, with a range of 25% to 75% according to the village, but with only moderate parasite loads; 2) a high level of parasitism by E. histolytica/E. dispar (17%), Stongyloides stercoralis (16%) and Hymenolepis nana (18%); 3) a lower level of parasitism by Ascaris lumbricoides and very low levels (almost absent) of Trichiuris trichiura; 4) the absence of Schistosoma and fluke eggs. With the exception of H. nana, which was more frequent in children than in adults, there was no significant difference in the level of parasitism according to sex and age. Although the Wayampi of French Guiana are French citizens and consequently have quite high incomes and ready access to clinics and medicines, intestinal parasites are far from under control in this population. A lack of fecal hygiene and the habit of walking barefoot are widespread in the unchanging Amazonian environment and contribute to this phenomenon.     

Evidence for the presence of serotonin in Mysidacea (Crustacea,Peracarida) as revealed by fluorescence immunohistochemistry

In crustaceans, serotonin (5-HT) exerts a wide range of physiological actions on many tissues. However, 5-HT has not been detected to date in Mysidacea (Crustacea, Peracarida). We have investigated the presence of 5-HT in the brain and the eyestalks of two Mysida (Leptomysis lingvura, Hemimysis margalefi) and one Lophogastrida (Lophogaster typicus) species by using the immunohistofluorescence technique. 5-HT-like immunopositive areas exhibit a similar pattern in the three species. 5-HT-like immunostaining is present in the retinular photosensitive cells, except in the deep-living species L. typicus. 5-HT-like cell bodies and fibres are observed in the lamina ganglionaris and in the three medullae. In the sinus gland, only 5-HT-like endings are detected. In the eyestalks, 5-HT-like fibres detected in the optic tract link with the protocerebrum, in which 5-HT-like somata and their extensions are found. Some neurones are detected in the anterior median cell cluster, in the protocerebral bridge and in the central body. In the deutocerebrum, the paracentral lobes are connected by immunoreactive fibres that run along the deutocerebral commissure. The glomeruli of the olfactory lobes exhibit strong diffuse immunostaining. Beside and in the median part of the deutocerebrum, at least two large serotoninergic neurones project their axons into the olfactory lobe cell cluster. Immunoreactive fibres are also found in the antennular neuropiles. Our results demonstrate the presence of 5-HT-like cell bodies and fibres in Mysidacea. The distribution patterns of the 5-HT immunoreactivity found herein are compared with those of other peracarids and decapods.