Low oxygen tension during in vitro maturation is beneficial for supporting the subsequent development of bovine cumulus-oocyte complexes

The effects of carbohydrates on meiotic maturation and ATP content of bovine oocytes under low oxygen tension (5%) were investigated. Furthermore, the developmental competence or intracellular H(2)O(2) contents of the oocytes matured under 5% or 20% O(2) was assessed. In vitro maturation of bovine cumulus-oocyte complexes was performed in synthetic oviduct fluid (SOF) containing 20 amino acids and hormones (SOFaa). The proportion of the oocytes that matured to the metaphase II stage in SOFaa containing 1.5 mM glucose, 0.33 mM pyruvate, and 3.3 mM lactate under 5% O(2) was dramatically lower than that of oocytes matured under 20% O(2) (P < 0.01). Similarly, the ATP content of the oocytes that matured under 5% O(2) was much lower than that of oocytes matured under 20% O(2) (P < 0.05). Under 5% O(2) the proportion of metaphase II oocytes increased with increasing glucose concentration (0-20 mM) in SOFaa without pyruvate or lactate. In addition, the ATP content of oocytes cultured in 20 mM glucose was higher (P < 0.05) than that of oocytes cultured in 1. 5 mM glucose. Two glucose metabolites (pyruvate and lactate) and a nonmetabolizable glucose analog (2-deoxy-glucose), however, had no noticeable effects on meiotic maturation under 5% O(2). These results suggest that ATP production under 5% O(2) is not dependent on the TCA cycle. Addition of iodoacetate, a glycolytic inhibitor, to SOFaa containing 20 mM glucose significantly reduced (P < 0.01) the proportion of metaphase II and ATP content. Moreover, the proportion of the development to the blastocyst stage of oocytes matured under 5% O(2) was higher (P < 0.05) than that of oocytes matured under 20% O(2). H(2)O(2) contents of oocytes matured under 5% O(2) was lower (P < 0.05) than that of oocytes matured under 20% O(2). The results of the present study demonstrate that glucose plays important roles in supporting the completion of meiotic maturation in bovine cumulus-oocyte complexes under low oxygen tension and that low oxygen tension during in vitro maturation is beneficial for supporting the subsequent development of bovine oocytes.     

Involvement of a small GTP-binding protein (G protein) regulator, small G protein GDP dissociation stimulator, in antiapoptotic cell survival signaling

Small GTP-binding protein GDP dissociation stimulator (Smg GDS) regulates GDP/GTP exchange reaction of Ki-Ras and the Rho and Rap1 family members and inhibits their binding to membranes. In fibroblasts, Smg GDS shows mitogenic and transforming activities in cooperation with Ki-Ras. However, the physiological function of Smg GDS remains unknown. Here we show that mice lacking Smg GDS died of heart failure shortly after birth, not resulting from developmental heart defects but from enhanced apoptosis of cardiomyocytes triggered by cardiovascular overload. Furthermore, neonatal thymocytes and developing neuronal cells underwent apoptotic cell death. Smg GDS-/- thymocytes were susceptible to apoptotic inducers, such as etoposide and UV irradiation. Smg GDS-/- thymocytes were protected from etoposide-induced cell death by ex vivo transduction of the Smg GDS cDNA. These phenotypes partly coincide with those observed in Ki-Ras-deficient mice, suggesting that Smg GDS is involved in antiapoptotic cell survival signaling through Ki-Ras.     

Age-dependent decreases of phosphorus and magnesium in human achilles’ tendons

To elucidate changes of human tendons with aging, the authors studied age-related changes of elements in human Achilles’ tendons by inductively coupled plasma-atomic emission spectrometry. The subjects consisted of seven men and seven women, ranging in age from 61 to 97 yr. It was found that the content of calcium increased progressively with aging in the Achilles’ tendons, whereas the contents of phosphorus and magnesium decreased gradually with aging. The previous investigations demonstrated that the content of calcium and phosphorus increased progressively with aging in most, but not all, human tissues, except for the bones. In ligaments, such as the anterior cruciate ligament and the ligament of the head of the femur, which are histologically similar to the Achilles’ tendon, it was previously found that both the contents of calcium and phosphorus increased with aging in the ligaments. It should be noted that the content of phosphorus in the Achilles’ tendons decreased during the aging process. In addition, it was found that there was a very high direct correlation between phosphorus and magnesium contents in the tendons, but not between calcium and phosphorus contents.     

Age-related changes of element contents in the human meniscus

The relative contents (RCs) of elements in the human menisci from 23 subjects in the age range between 65 and 93 yr were analyzed by inductively coupled plasma atomic emission spectrometry. The RCs of sulfur, calcium, and phosphorus in menisci increased progressively until the 80s, being the highest in the 80s, and thereafter decreased. The RCs of magnesium in menisci increased progressively until the 90s. Regarding the medial and lateral menisci, higher RCs of magnesium and iron, and a lower RC of phosphorus were found in lateral menisci in comparison with those in medial menisci. There were sexual differences in the RCs of calcium and phosphorus of medial and lateral menisci. The RCs of calcium and phosphorus were about 50% higher in women’s menisci than in men’s. Histological examinations showed that structureless mucoid masses were observed in the menisci, with very high RCs of calcium and phosphorus being detected.     

Gender difference in N170 elicited under oddball task

Background

Some studies have reported gender differences in N170, a face-selective event-related potential (ERP) component. This study investigated gender differences in N170 elicited under oddball paradigm in order to clarify the effect of task demand on gender differences in early facial processing.

Findings

Twelve males and 10 females discriminated targets (emotional faces) from non-targets (emotionally neutral faces) under an oddball paradigm, pressing a button as quickly as possible in response to the target. Clear N170 was elicited in response to target and non-target stimuli in both males and females. However, females showed more negative amplitude of N170 in response to target compared with non-target, while males did not show different N170 responses between target and non-target.

Conclusions

The present results suggest that females have a characteristic of allocating attention at an early stage when responding to faces actively (target) compared to viewing faces passively (non-target). This supports previous findings suggesting that task demand is an important factor in gender differences in N170.     

Characterisation of recombinant pyranose oxidase from the cultivated mycorrhizal basidiomycete <Emphasis Type="Italic">Lyophyllum shimeji</Emphasis> (hon-shimeji)

Background  

The flavin-dependent enzyme pyranose 2-oxidase (P2Ox) has gained increased attention during the last years because of a number of attractive applications for this enzyme. P2Ox is a unique biocatalyst with high potential for biotransformations of carbohydrates and in synthetic carbohydrate chemistry. Recently, it was shown that P2Ox is useful as bioelement in biofuel cells, replacing glucose oxidase (GOx), which traditionally is used in these applications. P2Ox offers several advantages over GOx for this application, e.g., its much broader substrate specificity. Because of this renewed interest in P2Ox, knowledge on novel pyranose oxidases isolated from organisms other than white-rot fungi, which represent the traditional source of this enzyme, is of importance, as these novel enzymes might differ in their biochemical and physical properties.     

10-Phenyl-[11]-cytochalasans from Indonesian mushroom Microporellus subsessilis

10-Phenyl-[11]-cytochalasans (4-6), together with three known derivatives (1-3), were isolated from the MeOH extract of the Indonesian mushroom Microporellus subsessilis by a bioassay-guided fractionation. The compounds 6 and 1-3 induced immotility in Artemia salina.     

An Arabidopsis homolog of yeast ATG6/VPS30 is essential for pollen germination

Yeast (Saccharomyces cerevisiae) Atg6/Vps30 is required for autophagy and the sorting of vacuolar hydrolases, such as carboxypeptidase Y. In higher eukaryotes, however, roles for ATG6/VPS30 homologs in vesicle sorting have remained obscure. Here, we show that AtATG6, an Arabidopsis (Arabidopsis thaliana) homolog of yeast ATG6/VPS30, restored both autophagy and vacuolar sorting of carboxypeptidase Y in a yeast atg6/vps30 mutant. In Arabidopsis cells, green fluorescent protein-AtAtg6 protein localized to punctate structures and colocalized with AtAtg8, a marker protein of the preautophagosomal structure. Disruption of AtATG6 by T-DNA insertion resulted in male sterility that was confirmed by reciprocal crossing experiments. Microscopic analyses of AtATG6 heterozygous plants (AtATG6/atatg6) crossed with the quartet mutant revealed that AtATG6-deficient pollen developed normally, but did not germinate. Because other atatg mutants are fertile, AtAtg6 likely mediates pollen germination in a manner independent of autophagy. We propose that Arabidopsis Atg6/Vps30 functions not only in autophagy, but also plays a pivotal role in pollen germination.     

Purification, cloning, and expression of an alpha/beta-galactoside alpha-2,3-sialyltransferase from a luminous marine bacterium, Photobacterium phosphoreum

A novel sialyltransferase, alpha/beta-galactoside alpha-2,3-sialyltransferase, was purified from the cell lysate of a luminous marine bacterium, Photobacterium phosphoreum JT-ISH-467, isolated from the Japanese common squid (Todarodes pacificus). The gene encoding the enzyme was cloned from the genomic library of the bacterium using probes derived from the NH(2)-terminal and internal amino acid sequences. An open reading frame of 409 amino acids was identified, and the sequence had 32% identity with that of beta-galactoside alpha-2,6-sialyltrasferase in Photobacterium damselae JT0160. DNA fragments that encoded the full-length protein and a protein that lacked the sequence between the 2nd and 24th residues at the NH(2) terminus were amplified by polymerase chain reactions and cloned into an expression vector. The full-length and truncated proteins were expressed in Escherichia coli, producing active enzymes of 0.25 and 305 milliunits, respectively, per milliliter of the medium in the lysate of E. coli. The truncated enzyme was much more soluble without detergent than the full-length enzyme. The enzyme catalyzed the transfer of N-acetylneuraminic acid from CMP-N-acetylneuraminic acid to disaccharides, such as lactose and N-acetyllactosamine, with low apparent K(m) and to monosaccharides, such as alpha-methyl-galactopyranoside and beta-methyl-galactopyranoside, with much lower apparent K(m). Thus, this sialyltransferase is unique and should be very useful for achieving high productivity in E. coli with a wide substrate range.     

A novel approach for myocardial regeneration with educated cord blood cells cocultured with cells from brown adipose tissue

Umbilical cord blood (CB) is a promising source for regeneration therapy in humans. Recently, it was shown that CB was a source of mesenchymal stem cells as well as hematopoietic stem cells, and further that the mesenchymal stem cells could differentiate into a number of cells types of mesenchymal lineage, such as cardiomyocytes (CMs), osteocytes, chondrocytes, and fat cells. Previously, we reported that brown adipose tissue derived cells (BATDCs) differentiated into CMs and these CMs could adapt functionally to repair regions of myocardial infarction. In this study, we examined whether CB mononuclear cells (CBMNCs) could effectively differentiate into CMs by coculturing them with BATDCs and determined which population among CBMNCs differentiated into CMs. The results show that BATDCs effectively induced CBMNCs that were non-hematopoietic stem cells (HSCs) (educated CB cells: e-CBCs) into CMs in vitro. E-CBCs reconstituted infarcted myocardium more effectively than non-educated CBMNCs or CD34-positive HSCs. Moreover, we found that e-CBCs after 3 days coculturing with BATDCs induced the most effective regeneration for impaired CMs. This suggests that e-CBCs have a high potential to differentiate into CMs and that adequate timing of transplantation supports a high efficiency for CM regeneration. This strategy might be a promising therapy for human cardiac disease.