Release of the Ca(2+) oscillation-inducing sperm factor during mouse fertilization

A cytosolic sperm protein(s), referred to as the sperm factor (SF), is thought to induce intracellular calcium ([Ca(2+)](i)) oscillations during fertilization in mammalian eggs. These oscillations, which are responsible for inducing complete egg activation, persist for several hours. Nevertheless, whether a protracted release of SF is responsible for the duration of the oscillations is unknown. Using a combination of intracytoplasmic sperm injection (ICSI), in vitro fertilization (IVF), sperm removal, reinjection of the withdrawn sperm, and [Ca(2+)](i) monitoring, we determined that 30 min was necessary for establishing oscillations. Importantly, a significant portion of the Ca(2+) activity became dissociated from the sperm within 15-60 min after entry, and by 120 min post-ICSI or IVF, sperm were unable to induce oscillations. The initiation of oscillations coincided with exposure and solubilization of the perinuclear theca (PT), as evidenced by transmission electron microscopy, although disassembly of the PT was not required for commencement of the [Ca(2+)](i) responses. Remarkably, despite its complete release into the ooplasm, SF associated with nuclear structures at the time of pronuclear formation. Lastly, release of SF was not affected by the cell cycle. We conclude that mouse sperm serves as a carrier for SF, which is rapidly and completely solubilized to establish [Ca(2+)](i) oscillations.     

Impaired resistance in early secondary Nippostrongylus brasiliensis infections in mice with defective eosinophilopoeisis

Eosinophils are an important feature of immune responses to infections with many of the tissue-invasive helminth parasites. The cytokine IL-5 and a high-affinity double GATA-binding site within the GATA-1 promoter are critical for eosinophilopoiesis. In this study, we believe we demonstrate for the first time that defects in eosinophilopoiesis are associated with impaired resistance to Nippostrongylus brasiliensis. Primary and secondary infections were established in wildtype (WT), IL-5(-/-) and DeltadblGATA mice. Resistance to secondary infections was impaired in IL-5(-/-) and DeltadblGATA mice, with significantly more larvae able to reach the lungs 2 days p.i. Pulmonary inflammation was minimal in all strains in the first 2 days of both primary and secondary infections, suggesting that eosinophil-dependent resistance occurred before larvae reached this site. Intestinal worm burdens and/or parasite egg production in primary infections were greater in animals with defective eosinophilopoiesis. While larvae did reach the gut by day 3 of secondary infections of WT and IL-5(-/-) mice, worms were expelled by day 7, even in the complete absence of eosinophils in tissues of the small intestine. This and our previous studies indicate that N. brasiliensis are likely to be exquisitely sensitive to attack by eosinophils soon after entry into the skin. Eosinophils in the gut may make a modest contribution to resistance on first exposure to the parasite, but are not required for expulsion in either primary or secondary infections. In order to mount an effective immune response it may be vital for the host to identify and attack the parasite before it implements immune evasion strategies and migrates to other anatomical sites. These observations may be of particular significance for the development of successful vaccines against hookworms and other nematodes.     

An additional editing site is present in apolipoprotein B mRNA.

Human intestinal apolipoprotein (apo) B mRNA undergoes a C to U RNA editing at nucleotide 6666 to generate a translation stop at codon 2153, which defines the carboxy-terminal of apo B48. Here we show that two of eleven human intestinal cDNAs spanning residue 6666 were edited from a genomically-encoded C to a T at residue 6802 as well as at residue 6666. This additional editing converts Thr (ACA) codon 2198 to Ile (AUA). Synthetic RNA including the nucleotide 6802 was edited in vitro by intestinal extracts at 10-15% of the editing efficiency of nucleotide 6666. A sequence is identified as important for recognition by the editing activity. No secondary structural homology was identified between the two edited sites. No other sequence in the region between 6411 and 6893 nucleotides of apo B mRNA was found to be edited in vivo or in vitro. Apo B RNA editing extracts from intestine did not edit maize cytochrome oxidase II mRNA.     

Noisy-threshold control of cell death

Background  

Cellular responses to death-promoting stimuli typically proceed through a differentiated multistage process, involving a lag phase, extensive death, and potential adaptation. Deregulation of this chain of events is at the root of many diseases. Improper adaptation is particularly important because it allows cell sub-populations to survive even in the continuous presence of death conditions, which results, among others, in the eventual failure of many targeted anticancer therapies.     

The antidepressant-like effect of Ocimum basilicum in an animal model of depression

We investigated the efficacy of Ocimum basilicum (OB) essential oils for treating depression related behavioral, biochemical and histopathological changes caused by exposure to chronic unpredictable mild stress (CUMS) in mice and to explore the mechanism underlying the pathology. Male albino mice were divided into four groups: controls; CUMS; CUMS plus fluoxetine, the antidepressant administered for pharmacological validation of OB; and CUMS plus OB. Behavioral tests included the forced swim test (FST), elevated plus-maze (EPM) and the open ?eld test (OFT); these tests were performed at the end of the experiment. We assessed serum corticosterone level, protein, gene and immunoexpression of brain-derived neurotropic factor (BDNF) and glucocorticoid receptors (GRs) as well as immunoexpression of glial fibrillary acidic protein (GFAP), Ki67, caspase-3 in the hippocampus. CUMS caused depression in the mice as evidenced by prolonged immobility in the FST, prolonged time spent in the open arms during the EPM test and reduction of open field activity in the OFT. OB ameliorated the CUMS induced depressive status. OB significantly reduced the corticosterone level and up-regulated protein and gene expressions of BDNF and GR. OB reduced CUMS induced hippocampal neuron atrophy and apoptosis, and increased the number of the astrocytes and new nerve cells. OB significantly increased GFAP-positive cells as well as BDNF and GR immunoexpression in the hippocampus.     

High sero-prevalence of caseous lymphadenitis identified in slaughterhouse samples as a consequence of deficiencies in sheep farm management in the state of Minas Gerais, Brazil

Background

Multiple congenital ocular anomalies (MCOA) syndrome is a hereditary congenital eye defect that was first described in Silver colored Rocky Mountain horses. The mutation causing this disease is located within a defined chromosomal interval, which also contains the gene and mutation that is associated with the Silver coat color (PMEL17, exon 11). Horses that are homozygous for the disease-causing allele have multiple defects (MCOA-phenotype), whilst the heterozygous horses predominantly have cysts of the iris, ciliary body or retina (Cyst-phenotype). It has been argued that these ocular defects are caused by a recent mutation that is restricted to horses that are related to the Rocky Mountain Horse breed. For that reason we have examined another horse breed, the Icelandic horse, which is historically quite divergent from Rocky Mountain horses.

Results

We examined 24 Icelandic horses and established that the MCOA syndrome is present in this breed. Four of these horses were categorised as having the MCOA-phenotype and were genotyped as being homozygous for the PMEL17 mutation. The most common clinical signs included megaloglobus, iris stromal hypoplasia, abnormal pectinate ligaments, iridociliary cysts occasionally extending into the peripheral retina and cataracts. The cysts and pectinate ligament abnormalities were observed in the temporal quadrant of the eyes. Fourteen horses were heterozygous for the PMEL17 mutation and were characterized as having the Cyst-phenotype with cysts and occasionally curvilinear streaks in the peripheral retina. Three additional horses were genotyped as PMEL17 heterozygotes, but in these horses we were unable to detect cysts or other forms of anomalies. One eye of a severely vision-impaired 18 month-old stallion, homozygous for the PMEL17 mutation was examined by light microscopy. Redundant duplication of non-pigmented ciliary body epithelium, sometimes forming cysts bulging into the posterior chamber and localized areas of atrophy in the peripheral retina were seen.

Conclusions

The MCOA syndrome is segregating with the PMEL17 mutation in the Icelandic Horse population. This needs to be taken into consideration in breeding decisions and highlights the fact that MCOA syndrome is present in a breed that are more ancient and not closely related to the Rocky Mountain Horse breed.     

Mitochondrial fragmentation in neurodegeneration

Mitochondria are remarkably dynamic organelles that migrate, divide and fuse. Cycles of mitochondrial fission and fusion ensure metabolite and mitochondrial DNA mixing and dictate organelle shape, number and bioenergetic functionality. There is mounting evidence that mitochondrial dysfunction is an early and causal event in neurodegeneration. Mutations in the mitochondrial fusion GTPases mitofusin 2 and optic atrophy 1, neurotoxins and oxidative stress all disrupt the cable-like morphology of functional mitochondria. This results in impaired bioenergetics and mitochondrial migration, and can trigger neurodegeneration. These findings suggest potential new treatment avenues for neurodegenerative diseases.