Effects of intracerebroventricular administration of opiate receptor antagonists on the suppressed pulsatile LH release during acute fasting in ovariectomized estradiol-treated rats.

The involvement of specific opiate receptors in the suppression of LH release during acute fasting in ovariectomized estradiol-treated rats was examined by intracerebroventricular (i.c.v.) administration of opiate receptor antagonists that exert a specificity directed mainly, although not absolutely, towards the delta-, kappa- or mu-opiate receptors. Fasting for 48 h significantly decreased mean plasma LH levels in estradiol-treated animals by increasing sensitivity to the negative feedback effect of estradiol. Injecting i.c.v. the mu-opiate receptor antagonist naloxone (10 or 100 nmol in 2 microliters of saline) blocked the inhibitory effect of fasting on pulsatile LH release and reinstated LH pulses. On the other hand, i.c.v. administration of the same dosages of a delta-opiate receptor antagonist ICI 174,864 or a kappa-opiate receptor antagonist WIN 44441-3 did not have any effect. These results suggest that the increased sensitivity of the LH-releasing mechanism to the negative feedback effect of estradiol during fasting involves the endogenous opioids mainly through the selective activation of the mu-opiate receptors.     

Seroprevalence of <Emphasis Type="Italic">Borrelia burgdorferi</Emphasis> sensu lato and <Emphasis Type="Italic">Anaplasma phagocytophilum</Emphasis> in Danish horses

Background

Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum are able to infect horses. However, the extend to which Danish horses are infected and seroconvert due to these two bacteria is unknown. The aim of the present study was to evaluate the seroprevalence of B. burgdorferi sensu lato and A. phagocytophilum in Danish horses.

Methods

A total of 390 blood samples collected from all major regions of Denmark and with a geographical distribution corresponding to the density of the Danish horse population were analyzed. All samples were examined for the presence of antibodies against B. burgdorferi sensu lato and A. phagocytophilum by the use of the SNAP^®4DX ^® ELISA test.

Results

Overall, 29.0% of the horses were seropositive for B. burgdorferi sensu lato whereas 22.3% were seropositive for A. phagocytophilum.

Conclusions

Antibodies against B burgdorferi sensu lato and A. phagocytophilum are commonly found among Danish horses thus showing that Danish horses are frequently infected by these organisms.

     

Ribonuclease Activity in Normal, opaque-2, and floury-2 Maize Endosperm during Development

The elevated ribonuclease activity produced in the endosperm of a maize (Zea mays L.) inbred, W64A, by homozygous opaque-2, results from a more than doubled rate of ribonuclease accumulation occurring prior to 16 days post-pollination; after 16 days the rates in opaque-2 and normal are the same, suggesting that opaque-2 is no longer active. The pattern of ribonuclease increase in the opaque-2 dosage series indicates that opaque-2 is not fully recessive. Ribonuclease accumulation is not affected by floury-2 in a second inbred, B14. The results are discussed with reference to other proteins, notably zein, the net synthesis of which is affected by opaque-2.     

Biochemical factors affecting protein accumulation in the rice grain

Rice grains (Oryza sativa L.) from three varieties and three pairs of lines with different protein content were collected at 4-day intervals from 4 to 32 days after flowering. The samples were analyzed for protein, free amino nitrogen, ribonucleic acid, protease activity, and ribonuclease activity. In addition, the capacity of the intact grain to incorporate amino acids was determined for the three pairs of lines. The maximal level of free amino nitrogen and the capacity of the developing grain to incorporate amino acids were consistently found to be higher in the samples with the high protein content in the mature grain. The ribonucleic acid content of the grain tended to be higher in the high protein samples.     

Estimates of DNA and protein sequence divergence: an examination of some assumptions

Some of the assumptions underlying estimates of DNA and protein sequence divergence are examined. A solution for the variance of these estimates that allows for different mutation rates and different population sizes in each species and for an arbitrary structure in the initial population is obtained. It is shown that these conditions do not strongly affect estimates of divergence. In general, they cause the variance of divergence to be smaller than a binomial variance. Thus, the binomial variance that is usually assumed for these estimates is safely conservative. It is shown that variability in the mutation rate among sites can have an effect as large as or larger than variability in the mutation rate among bases. Variability in the mutation rate among bases and among sites causes the number of substitutions between two sequences to be underestimated. Protein and DNA sequences from several species are collected to estimate the variability in mutation rates among sites. When many homologous sequences are known, standard methods to estimate this variability can be used. The estimates of this variability show that this factor is important when considering the spectrum of spontaneous mutations and is strongly reflected in the divergence of sequences. Smaller variability is found for the third position of codons than for the first and second codon positions. This may be because of less selective constraints on this position or because the third position has been saturated with mutations for the sequences examined.      

Molecular phylogeny of diplomonads and enteromonads based on SSU rRNA,alpha-tubulin and HSP90 genes: Implications for the evolutionary history of the double karyomastigont of diplomonads

Background  

Fornicata is a relatively recently established group of protists that includes the diplokaryotic diplomonads (which have two similar nuclei per cell), and the monokaryotic enteromonads, retortamonads and Carpediemonas, with the more typical one nucleus per cell. The monophyly of the group was confirmed by molecular phylogenetic studies, but neither the internal phylogeny nor its position on the eukaryotic tree has been clearly resolved.     

Statins but not fibrates improve the atherogenic to anti-atherogenic lipoprotein particle ratio: a randomized crossover study

Background  

Prior studies suggested low density lipoprotein particle (LDLP) size is a predictor of atherosclerosis. Knowledge of effects of lipid lowering drugs on lipoprotein subclasses is useful. We treated subjects with hyperlipidemia sequentially with statins and fibrates, the 2 main classes of lipid lowering therapy and studied changes in NMR lipoprotein subclasses.     

New insights in Salicornia L. and allied genera (Chenopodiaceae) inferred from nrDNA sequence data

A phylogenetic analysis was performed based on ITS DNA sequences of fourteen samples from different sources of six species of Salicornia, the three allied genera Arthrocnemum, Sarcocornia and Halocnemum of the same tribe Salicornieae, and other genera of the subfamily Salicornioideae used in previous studies. Bassia hirsuta, Camphorosma monspeliaca (subfamily Chenopodioideae) and four species of Suaeda (subf. Suaedoideae) were chosen as outgroups. Results show that the annual genus Salicornia is a sister group to the perennial genera Sarcocornia, Arthrocnemum and Halocnemum. Moreover, the phylogenetic analysis based on ITS results distinguished two groups of Salicornia species which fitted with ploidy level: one group consisted of diploid species, and the second of tetraploid ones. Sarcocornia and Arthrocnemum are shown to be closely related, even though the species investigated here exhibited an evident distance between their ITS sequences. On the basis of our results, these two genera should be united. Bienertia (already separated as Bienertieae) was confirmed as probable outgroup to the subf. Salicornioideae, while Kalidium (subf. Salicornioideae, tribe Halopeplideae) was an outgroup to the rest of the Salicornioideae (tribe Salicornieae). The group Allenrolfea plus Halocnemum was the most basal of the tribe Salicornieae amongst those investigated in this study. The two samples of Halocnemum strobilaceum used in this work displayed numerous changes (transitions and transversions) in their respective sequences, probably related to their morphological and chorological differentiation. On the basis of our analysis, the most probable basal chromosome number for Salicornieae appears to be 2n = 18. The same number would also be the base number for the annual genus Salicornia and the perennial Arthrocnemum ( + Sarcocornia), with polyploidy arising independently in the two groups.