Dynamin 1 Restrains Vesicular Release to a Subquantal Mode In Mammalian Adrenal Chromaffin Cells.

Dynamin 1 (dyn1) is required for clathrin-mediated endocytosis in most secretory (neuronal and neuroendocrine) cells. There are two modes of Ca2+-dependent catecholamine release from single dense-core vesicles: full-quantal (quantal) and subquantal in adrenal chromaffin cells, but their relative occurrences and impacts on total secretion remain unclear. To address this fundamental question in neurotransmission area using both sexes of animals, here we report the following: (1) dyn1-KO increased quantal size (QS, but not vesicle size/content) by ≥250% in dyn1-KO mice; (2) the KO-increased QS was rescued by dyn1 (but not its deficient mutant or dyn2); (3) the ratio of quantal versus subquantal events was increased by KO; (4) following a release event, more protein contents were retained in WT versus KO vesicles; and (5) the fusion pore size (dp) was increased from ≤9 to ≥9 nm by KO. Therefore, Ca2+-induced exocytosis is generally a subquantal release in sympathetic adrenal chromaffin cells, implying that neurotransmitter release is generally regulated by dynamin in neuronal cells.SIGNIFICANCE STATEMENT Ca2+-dependent neurotransmitter release from a single vesicle is the primary event in all neurotransmission, including synaptic/neuroendocrine forms. To determine whether Ca2+-dependent vesicular neurotransmitter release is "all-or-none" (quantal), we provide compelling evidence that most Ca2+-induced secretory events occur via the subquantal mode in native adrenal chromaffin cells. This subquantal release mode is promoted by dynamin 1, which is universally required for most secretory cells, including neurons and neuroendocrine cells. The present work with dyn1-KO mice further confirms that Ca2+-dependent transmitter release is mainly via subquantal mode, suggesting that subquantal release could be also important in other types of cells.

Porous calcium sulfate ceramics with tunable degradation rate.

It would be ideal if bone substitutes could be absorbed by the human body upon the formation of new bone. Although calcium sulfate is absorbable, its biodegradation rate is very fast. Fortunately, this rate can be reduced significantly through various sintering techniques. This study demonstrates that the degradation rate of sintered CS specimens can be adjusted through the introduction of pores. Through various techniques, we introduced spherical pores with amounts ranging from 6.7 to 68 % into sintered CS specimens. The corresponding degradation rate in Hank's solution varied from 1.9 to 7.7 %/day and the cytotoxicity test results indicated low toxicity within the sintered CS specimens.

Association of depression and antidepressant therapy with antiretroviral therapy adherence and health-related quality of life in men who have sex with men.

UNAIDS' HIV treatment targets require that 90% of people living with HIV/AIDS (PLWHA) receiving antiretroviral treatment (ART) achieve viral suppression and 90% of people with viral suppression have good health-related quality of life (HRQOL). This study aimed to examine the association of depression and antidepressant therapy with ART adherence and HRQOL in HIV-infected men who have sex with men (MSM). From 2018 through 2020, HIV-infected MSMs were consecutively recruited (N = 565) for the evaluation of ART adherence and HRQOL at Taipei City Hospital HIV clinics. Non-adherence to ART was defined as a Medication Adherence Report Scale score of < 23. HRQOL in PLWHHA was evaluated using WHOQOL-BREF, Taiwan version. Overall, 14.0% had depression and 12.4% exhibited non-adherence to ART. The nonadherence proportion was 21.8% and 10.5% in depressed and nondepressed HIV-infected MSM, respectively. After adjusting for other covariates, depression was associated with a higher risk of nonadherence to ART (adjusted odds ratio = 2.02; 95% confidence interval: 1.02-4.00). Physical, psychological, social, and environmental HRQOL were significantly negatively associated with depression. Considering antidepressant therapy, ART nonadherence was significantly associated with depression without antidepressant therapy but not with antidepressant therapy. The depressed HIV-infected MSM without antidepressant therapy had worse psychological, social, and environmental HRQOL than those with antidepressant therapy. Our study suggests that depression is associated with poor ART adherence and HRQOL, particularly in those without antidepressant therapy. Adequate diagnosis and treatment of depression should be provided for PLWHA to improve their ART adherence and HRQOL.

Novel avian metaavulavirus isolated from birds of the family Columbidae in Taiwan.

Avian paramyxoviruses (APMVs) consist of twenty known species and have been isolated from domestic and wild birds around the world. In 2009, the isolate APMV/dove/Taiwan/AHRI33/2009 was isolated from swabs of red turtle doves (Streptopelia tranquebarica) during active surveillance of avian influenza in resident birds in Taiwan, and it was initially identified as paramyxovirus based on electron microscopy. Hemagglutination inhibition assays indicated antigenic heterogeneity of AHRI33 with the known APMV-1, -2, -3, -4, -6, -8, and -9 species, only showing weak but measurable cross-reactivity with APMV-7. Pathogenicity ICPI test revealed that the virus was avirulent for chickens. The AHRI33 virus genome revealed a typical APMV structure consisting of six genes 3'-NP-P-M-F-HN-L-5', and the length of the genome was 16,914 nucleotides, the third longest among the members of the subfamily Avulavirinae. Estimates of the nucleotide sequence identities of the genome between each prototype of APMVs had shown AHRI33 to be more closely related to APMV-7 than to the others, with a sequence identity of 62.8%. Based on topology of the phylogenetic tree of RdRp genes and the branch length between the nearest node and the tip of the branch, AHRI33 met the criteria for designation as distinct species. Together, the data suggest that the isolate APMV/dove/Taiwan/AHRI33/2009 should be considered as the prototype strain of the new species Avian metaavulavirus 21 in the genus Metaavulavirus in the subfamily Avulavirinae.

Assessment of fish iridoviruses using a novel cell line GS-1, derived from the spleen of orange-spotted grouper Epinephelus coioides (Hamilton) and susceptible to ranavirus and megalocytivirus.

A new cell line (GS-1) was developed from the spleen tissue of the orange-spotted grouper, Epinephelus coioides applied for viral infection studies of fish ranavirus and megalocytivirus. The cells proficiently multiplied in Leibovitz's L-15 medium supplemented with 10% fetal bovine serum at temperatures between 20°C and 32°C. Morphologically, the cell line comprised fibroblast-like cells, and this was confirmed by immunostaining with vimentin, fibronectin, and desmin antibodies. The optimal temperature for grouper iridovirus (GIV) and infectious spleen and kidney necrosis virus (ISKNV) proliferation in GS-1 cells was 25°C, and the highest titer of GIV was 108.4 TCID50/ml, and the highest titer of ISKNV was 105.2 TCID50/ml. Electron micrographs showed that the mean diameter of GIV virions was 180-220 nm, which was larger than ISKNV virions (160-200 nm). Negatively stained GIV particles possessed an envelope structure that was assembled by the three-layered structure with an inner electron-dense core surrounded by a lighter coat (mean diameter, 27 ± 3 nm). The highest GIV-induced mortality of groupers occurred at 25°C, whereas the highest ISKNV-induced mortality occurred at 30°C. In summary, GS-1 cell line is a valuable tool for isolating and investigating fish ranavirus and megalocytivirus in the same host system.

Recovery evaluation of rats' damaged tibias: Implantation of core-shell structured bone scaffolds made using hollow braids and a freeze-thawing process.

This study prepares biodegradable bone scaffolds helping the recovery of damaged tibias of rats. Polyvinyl alcohol (PVA) plied yarns are fabricated into hollow braids. The braids are combined with hydroxyapatite (HA)/gelatin/PVA mixtures and processed using freeze-thawing and freeze-drying processes in order to form bone scaffolds. These bone scaffolds are observed by scanning electron scope (SEM) and tested for compression strength. Afterwards, recovery of damaged bone, the morphology of the bone, and the histological observation are evaluated. Results indicate a small amount of HA helps in enhancing the compressive strength of bone scaffolds. Results of in vivo assay indicate the damaged tibias of rats recover and function well eight weeks after the implantation, and exhibit a normal morphology. Histological observation confirms the bone scaffolds gradually decompose, allowing tissue infiltration and facilitating ossification. This study successfully produces bone scaffolds with satisfactory mechanical properties helping in the recovery of damaged tibias of rats.

Suppression of influenza virus infection by the orf virus isolated in Taiwan.

Orf virus (ORFV), a member of parapoxvirus, is an enveloped virus with genome of double-stranded DNA. ORFV causes contagious pustular dermatitis or contagious ecthyma in sheep and goats worldwide. In general, detection of viral DNA and observing ORFV virion in tissues of afflicted animals are two methods commonly used for diagnosis of orf infection; however, isolation of the ORFV in cell culture using virus-containing tissue as inoculum is known to be difficult. In this work, the ORFV (Hoping strain) isolated in central Taiwan was successfully grown in cell culture. We further examined the biochemical characteristic of our isolate, including viral genotyping, viral mRNA and protein expression. By electron microscopy, one unique form of viral particle from ORFV infected cellular lysate was demonstrated in the negative-stained field. Moreover, immunomodulating and anti-influenza virus properties of this ORFV were investigated. ORFV stimulated human monocytes (THP-1) secreting proinflammatory cytokines IL-8 and TNF-α. And, pre-treatment of ORFV-infected cell medium prevents A549 cells from subsequent type A influenza virus (IAV) infection. Similarly, mice infected with ORFV via both intramuscular and subcutaneous routes at two days prior to IAV infection significantly decreased the replication of IAV. In summary, the results of a current study indicated our Hoping strain harbors the immune modulator property; with such a bio-adjuvanticity, we further proved that pre-exposure of ORFV protects animals from subsequent IAV infection.

Improving biodegradation behavior of calcium sulfate bone graft tablet by using water vapor treatment.

The biodegradation rate of calcium sulfate hemihydrate (CSH) tablets is extremely rapid. This study adopts a water vapor treatment to modify the surface structure of a CSH tablet. After the treatment, a small amount of calcium sulfate dihydrate (CSD) forms on the surface; the porosity near the surface region decreases, consequently enhancing tablet strength and surface hardness. Because of the decrease in porosity at the surface, the time for complete disintegration increases from 1.2 h to 7.2 h; the time for complete dissolution increases from 7 days to 25 days.

Impulse-dependent extracellular resting dopamine concentration in rat striatum in vivo.

The ambient resting dopamine (DA) concentration in brain regulates cognition and motivation. Despite its importance, resting DA level in vivo remains elusive. Here, by high-frequency stimulation of the medial forebrain bundle and immediately following the stimulus-induced DA overflow, we recorded a DA "undershoot" which is a temporal reduction of DA concentration to a level below the baseline. Based on the DA undershoot, we predicted a resting DA concentration of ∼73nM in rat striatum in vivo. Simulation studies suggested that removing basal DA by DAT during the post-stimulation inhibition of tonic DA release caused the DA undershoot, and the resting concentration of DA modulated the kinetics of the evoked DA transient. The DA undershoot was eliminated by either blocking D2 receptors with haloperidol or blocking the DA transporter (DAT) with cocaine. Therefore, the impulse-dependent resting DA concentration is in the tens of nanomolar range and is modulated by the presynaptic D2 receptors and the DAT in vivo.

Phylogenetic analysis of parapoxviruses and the C-terminal heterogeneity of viral ATPase proteins.

Two outbreaks of orf virus (a parapoxvirus) infection in goats found in Nantou and Taiping of central Taiwan were investigated. The nucleotide and the amino acid sequences of viral B2L, E3L and A32L genes in these two outbreaks were analyzed, and each of their phylogenetic trees were also constructed. In the A32L gene, an unexpected deletion of 24 nucleotides was found in the Taiping strain. The A32L gene can encode an ATPase and is supposed to be involved in virion DNA packaging. The 24 nucleotides correspond to 8 amino acids residues of the viral ATPase, which are located near the C-terminal region of the enzyme. Moreover, two copies of the RGD sequence at C-terminal region of ATPase were found in the Nantou strain. The 24-nucleotide difference in the A32L gene indicated that the Nantou strain and the Taiping strain were two separate strains, and it can be used in differential molecular diagnosis. Moreover, the C-terminal heterogeneity was found to be a general feature of the viral ATPase. Lastly, similar functional motifs of the ATPase and the Ras proto-oncoprotein (a GTPase) are discussed.