Differentiation of female primordial germ cells in the male testes of chicken (Gallus gallus domesticus)

In our previous studies, we demonstrated that female primordial germ cells (PGCs) have the ability to differentiate into W chromosome-bearing (W-bearing) spermatozoa in male gonads of germline chimeric chickens. In this study, to investigate the differentiation pattern of female PGCs in male gonads in chickens, three germline chimeric chickens were generated by injecting female PGCs into the male recipient embryos. After these male chimeras reached sexual maturity, the semen samples were analyzed for detecting W-bearing cells by PCR and in situ hybridization analyses. The results indicated that the female PGCs had settled and differentiated in their testes. A histological analysis of the seminiferous tubule in those chimeras demonstrated that the W-bearing spermatogonia, spermatocytes, and round spermatids accounted for 30.8%, 32.7%, and 28.4%, respectively. However, the W-bearing elongating spermatid was markedly lower (7.7%) as compared to the W-bearing round spermatid. The W-bearing spermatozoa were hardly ever observed (0.2%). We concluded that although female PGCs in male gonads are capable of passing through the first and second meiotic division in adapting themselves to a male environment, they are hardly complete spermiogenesis.     

Activation of Rac1 by Rho-guanine nucleotide dissociation inhibitor-beta with defective isoprenyl-binding pocket

Rho-guanine nucleotide dissociation inhibitor-beta (RhoGDIbeta), a regulator for Rho GTPases, is implicated in cancer cell progression. We reported that C-terminal truncated RhoGDIbeta (DeltaC(166-201)-RhoGDIbeta) promoted metastasis through activating Rac1 signaling pathway in ras-transformed fibroblast cells. To better understand the mechanism of Rac1 activation by DeltaC(166-201)-RhoGDIbeta during metastasis, the amount of GTP-bound Rac1 was measured as the activation level of Rac1 in cells expressing various mutant RhoGDIbeta with sequential C-terminal deletions. Three C-terminal hydrophobic amino acid residues (Trp191, Leu193, and Ile195) supposed to interact with isoprenyl groups of Rac1, was indispensable for a proper regulation of Rac1 activation/inhibition. Deletion of this region led RhoGDIbeta to continuously associate with GTP-bound Rac1, provoking constitutive activation of Rac1. Thus, impaired interaction of RhoGDIbeta with Rac1 isoprenyl groups possibly makes RhoGDIbeta function as a positive regulator for Rac1 during metastasis.     

<Emphasis Type="Italic">Norrisiella sphaerica</Emphasis> gen. et sp. nov., a new coccoid chlorarachniophyte from Baja California,Mexico

A new chlorarachniophyte, Norrisiella sphaerica S. Ota et K. Ishida gen. et sp. nov., from the coast of Baja California, Mexico is described. We examined its morphology, ultrastructure, and life cycle in detail, using light microscopy, transmission electron microscopy, and time-lapse videomicroscopy. We found that this chlorarachniophyte possessed the following characteristics: (1) vegetative cells were coccoid and possessed a cell wall, (2) a pyrenoid was slightly invaded by plate-like periplastidial compartment from the tip of the pyrenoid, (3) a nucleomorph was located near the pyrenoid base in the periplastidial compartment, (4) cells reproduced vegetatively via autospores, and (5) a flagellate stage was present in the life cycle. This combination of characteristics differs from any of the described chlorarachniophyte genera, and therefore a new genus is established. Fluorescent microscopic observations suggested that the alga formed multinucleate cells prior to forming autospores. Time-lapse observations during autospore formation showed that cytokinesis occurred simultaneously in the multinucleate cells. Zoospores were also produced, and video sequences captured the release of zoospores from coccoid cells. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Hyperplastic polyps and sessile serrated ‘adenomas’ of the colon and rectum display gastric pyloric differentiation

The serrated polyp-neoplasia pathway is a novel concept that has been demonstrated to differ from the conventional adenoma-carcinoma pathway. To characterize the phenotypic patterns of differentiation in colorectal serrated polyps, we examined the immunohistochemical expression profile of gastric (MUC5AC, TFF1, MUC6, GlcNAcα1 → 4Gal → R, and PDX1) and intestinal (MUC2, TFF3, and CDX2) epithelial markers in 15 hyperplastic polyps (HPs), 29 sessile serrated adenomas (SSAs),12 traditional serrated adenomas (TSAs), and 16 conventional adenomas (CAs). MUC5AC and TFF1 were upregulated in the HPs, SSAs, and TSAs. MUC6 was expressed in the HPs and SSAs. GlcNAcα1 → 4Gal → R was expressed only in the SSAs. Although MUC2 expression was preserved, TFF3 was downregulated in the HPs, SSAs, and TSAs. PDX1 was upregulated in the HPs, SSAs, and TSAs. On the other hand, CDX2 was downregulated in the HPs and SSAs. The colorectal serrated polyps showed higher expression of gastric makers than CAs. The HPs and SSAs showed gastric and intestinal mixed phenotype expression with gastric pyloric organoid differentiation and almost identical, but different from the TSAs, marker profile. PDX1 up-regulation and CDX2 down-regulation could be important for the induction of a gastric pyloric pattern of cell differentiation in colorectal serrated polyps.     

Analysis of expressed sequence tags from the fungus Aspergillus oryzae cultured under different conditions.

We performed random sequencing of cDNAs from nine biologically or industrially important cultures of the industrially valuable fungus Aspergillus oryzae to obtain expressed sequence tags (ESTs). Consequently, 21 446 raw ESTs were accumulated and subsequently assembled to 7589 non-redundant consensus sequences (contigs). Among all contigs, 5491 (72.4%) were derived from only a particular culture. These included 4735 (62.4%) singletons, i.e. lone ESTs overlapping with no others. These data showed that consideration of culture grown under various conditions as cDNA sources enabled efficient collection of ESTs. BLAST searches against the public databases showed that 2953 (38.9%) of the EST contigs showed significant similarities to deposited sequences with known functions, 793 (10.5%) were similar to hypothetical proteins, and the remaining 3843 (50.6%) showed no significant similarity to sequences in the databases. Culture-specific contigs were extracted on the basis of the EST frequency normalized by the total number for each culture condition. In addition, contig sequences were compared with sequence sets in eukaryotic orthologous groups (KOGs), and classified into the KOG functional categories.     

Metformin prevents methylglyoxal-induced apoptosis of mouse Schwann cells

Methylglyoxal (MG) is involved in the pathogenesis of diabetic complications via the formation of advanced glycation end products (AGEs) and reactive oxygen species (ROS). To clarify whether the antidiabetic drug metformin prevents Schwann cell damage induced by MG, we cultured mouse Schwann cells in the presence of MG and metformin. Cell apoptosis was evaluated using Hoechst 33342 nuclear staining, caspase-3 activity, and c-Jun-N-terminal kinase (JNK) phosphorylation. Intracellular ROS formation was determined by flow cytometry, and AMP-activated kinase (AMPK) phosphorylation was also examined. MG treatment resulted in blunted cell proliferation, an increase in the number of apoptotic cells, and the activation of caspase-3 and JNK along with enhanced intracellular ROS formation. All of these changes were significantly inhibited by metformin. No significant activation of AMPK by MG or metformin was observed. Taken together, metformin likely prevents MG-induced apoptotic signals in mouse Schwann cells by inhibiting the formation of AGEs and ROS.     

Effect of Azithromycin on Mineralized Nodule Formation in MC3T3-E1 Cells

Azithromycin displays immunomodulatory and anti-inflammatory effects in addition to broad-spectrum antimicrobial activity and is used to treat inflammatory diseases, including respiratory and odontogenic infections. Few studies have reported the effect of azithromycin therapy on bone remodeling processes. The aim of this study was to examine the effects of azithromycin on the osteogenic function of osteoblasts using osteoblast-like MC3T3-E1 cells. Cells were cultured in the presence of 0, 0.1, 1, and 10 µg/mL azithromycin, and cell proliferation and alkaline phosphatase (ALPase) activity were determined. In vitro mineralized nodule formation was detected with alizarin red staining. The expression of collagenous and non-collagenous bone matrix protein was determined using real-time PCR or enzyme-linked immunosorbent assays. In cells cultured with 10 µg/mL azithromycin, the ALPase activity and mineralized nodule formation decreased, while the type I collagen, bone sialoprotein, osteocalcin, and osteopontin mRNA expression as well as osteopontin and phosphorylated osteopontin levels increased. These results suggest that a high azithromycin concentration (10 µg/mL) suppresses mineralized nodule formation by decreasing ALPase activity and increasing osteopontin production, whereas low concentrations (≤l.0 µg/mL) have no effect on osteogenic function in osteoblastic MC3T3-E1 cells.     

A special issue of the Australian society for Biophysics

On behalf of the Australian Society for Biophysics (ASB) and the Editors of this Special Issue, I would like to express our appreciation to Editor-in-Chief, Damien Hall, for arranging the publication of this Special Issue. The ASB is about five times smaller than our sister the Biophysical Society for Japan (BSJ) and tenfold smaller than the US Biophysical Society (USBS), but our meetings are notable because of the encouragement the Society gives to emerging biophysicists. It can be a terrifying experience for a PhD student to have to face a roomful of professors and senior academics, but invariably they appreciate the experience. Another feature of the ASB meetings is the inclusion of contributions from the Asian Pacific region. We now have formal ties with our New Zealand colleagues and our meetings with the BSJ contain joint sessions (see below). In 2020, despite the impact of COVID-19 (see Adam Hill’s Commentary), there is a joint session with the University of California Davis. This Special Issue comprises 2 Editorials, 3 Commentaries, and 25 reviews.

When we began to put together an editorial on the contributions to this Special Issue of the 44th meeting of the Australian Society for Biophysics (ASB), we were struck by the sheer diversity of what we call “Biophysics”. Biophysics is actually not easy to define. The glib answer is “Biophysics is what biophysicists do”, but what do they do? If we asked an Australian Minister for Science to tell us what biophysicists do, he or she could tell us what immunologists and virologists do, but would probably have no idea what a biophysicist does. So how should we explain biophysics to the Minister? The US Biophysical Society defines “biophysics” as the field that applies the theories and methods of physics to understand how biological systems work. Operationally, biophysicists analyse the structure of biological molecules like DNA and proteins, they develop computer models to understand how drugs bind to the receptors in the body, and they investigate how gene mutations change the function of proteins.We thought a good example of biophysics research is the article by Boris Martinac at the beginning of this Special Issue. Boris has worked for much of his research life on trying to figure out how a mechanosensitive ion channel works. His “babies” are molecules encoded by the MscL and MscS genes and more recently also by the Piezo1 gene. He realised that bacteria needed to have sensors embedded in their surface membrane so they can quickly produce electrical or chemical signals in response to a mechanical force which occurs in the form of osmotic pressure. This of course is what enables the bacterium to survive when exposed to a hypoosmotic shock. More recently he and his colleagues turned their attention to investigating whether Piezo1 channels are the inherently mechanosensitive channels in vertebrates (Syeda et al. 2016) like MscL and MscS channels are in bacteria. They explained how Piezo receptors respond to changes in mechanical curvature of the cell membranes that open non-specific cation channels, thereby generating an electrical signal. In 2013 Boris was elected to the Australian Academy of Science in recognition of his discovery of bacterial mechanosensitive channels and the physical principles of mechanosensitive channel gating. More recently his work has expanded into the roles of mechanosensitive channels in nerves and heart disease. While we all hope he would get the “big” prize in science, it was his colleague, Ardem Patapoutian, who was awarded a share for the 2021 Nobel Prize in Physiology or Medicine for his research on Piezo1 and Piezo2.The 44th meeting of the Australian Society for Biophysics (ASB) was notable for two other reasons. It was either despite the fact or because it was a virtual meeting that the Society concurrently ran an international symposium with our sister society in Japan the Japanese Society for Biophysics. There is a close connection between the ABS and JSB. For years they have encouraged Australian biophysicists to travel to the large JSB meetings in Japan and they regularly send a strong contingent to Australia. A lot of hard work was put in by Kumiko Hayashi and her colleagues Risa Shibuya and Emi Hibino and the meeting attracted Japanese biophysicists from Tsukuba, Osaka, Kyoto, Shinjuku, Okayama, Kawasaki and Nagoya.The Society also hosted a virtual Early Career Researcher symposium which involved ASB and the University of California Davis. This was chaired by Dr Adam Hill and we refer you to his Commentary where he writes about the challenges and successes of running a virtual meeting “Biophysics in the time of COVID”.The ASB has had a long-standing policy to encourage presentations from early career biophysicists, even as early as PhD students. These young biophysicists prepare carefully and seem to enjoy what can be a terrifying experience. Professor Jamie Vandenberg moderated a session on careers in biophysics where participants discussed the latest technology in ultrasound, the Victor Chang Innovation Centre, strategies for careers outside of traditional biophysics, the importance of scientific communication and advocacy, and the importance intellectual property law, and finally, there were some encouraging words on a career in biophysics from Boris Martinac.Our friends across the “ditch” in New Zealand had a session that discussed calcium imaging in mouse models of disease, the impact fibrosis on Ca signalling, high-content super-resolution microscopy, effects of ryanodine receptor clustering on arrhythmia, the impact of fibrosis on cardiac Ca signalling, how N-glycans affect shear force activation of Na channels, and a fascinating analysis of how insects have managed to adapt their flight muscles to achieve high-frequency flapping flight.The meeting finished with a presentation of the McAuley-Hope prize for a biophysicist who crosses boundaries in biophysics and develops new techniques and methods. It is not always presented but Dr Till Boecking at the University of New South Wales was the well-deserved winner of this much sought-after Prize.     

Corticotropin-releasing hormone and pituitary-adrenocortical responses in chronically stressed rats

Brain corticotropin-releasing hormone (CRH) concentration and pituitary adreno-cortical responses were examined in chronically stressed rats: body restraint stress (6 h/day) for 4 or 5 weeks. Stressed rats showed a reduction in weight gain. CRH concentration in the median eminence and the rest of the hypothalamus were not different between control and chronically immobilized rats. The anterior pituitary adenocorticotropic hormone (ACTH) concentration was elevated in chronically stressed rats, whereas plasma ACTH and corticosterone levels did not differ from the control values. The median eminence CRH concentration was reduced to the same extent at 5 min after onset of ether exposure (1 min) in chronically immobilized rats and controls. However, plasma ACTH and corticosterone showed greater responses to ether stress in chronically immobilized rats than in control rats. Plasma ACTH and corticosterone responses to exogenous CRH were not different between control and chronically immobilized rats, while the response to arginine vasopressin (AVP) was significantly greater in chronically immobilized rats. These results suggest that chronic stress caused an increase in the ACTH-secreting mechanism and that pituitary hypersensitivity to vasopressin might at least be partly responsible for this.     

Characterization of ATPase activity in the mycelial form cells of yeast Saccharomycopsis fibuligera

1. The properties of ATPase activity were studied with the mycelial form cells of Saccharomycopsis fibuligera. 2. Optimal pH for the activity was about 9.5. 3. The activity was stimulated by Mg2+. 4. The activity was inhibited by DCCD, NaF and oligomycin, but not inhibited by ouabain.