Aquatic models of human ciliary diseases

Cilia are microtubule‐based structures that either transmit information into the cell or move fluid outside of the cell. There are many human diseases that arise from malfunctioning cilia. Although mammalian models provide vital insights into the underlying pathology of these diseases, aquatic organisms such as Xenopus and zebrafish provide valuable tools to help screen and dissect out the underlying causes of these diseases. In this review we focus on recent studies that identify or describe different types of human ciliopathies and outline how aquatic organisms have aided our understanding of these diseases.     

Calcium/Calmodulin-Dependent Protein Kinase Is Negatively and Positively Regulated by Calcium,Providing a Mechanism for Decoding Calcium Responses during Symbiosis Signaling

The establishment of symbiotic associations in plants requires calcium oscillations that must be decoded to invoke downstream developmental programs. In animal systems, comparable calcium oscillations are decoded by calmodulin (CaM)–dependent protein kinases, but symbiotic signaling involves a calcium/CaM–dependent protein kinase (CCaMK) that is unique to plants. CCaMK differs from the animal CaM kinases by its dual ability to bind free calcium, via calcium binding EF-hand domains on the protein, or to bind calcium complexed with CaM, via a CaM binding domain. In this study, we dissect this dual regulation of CCaMK by calcium. We find that calcium binding to the EF-hand domains promotes autophosphorylation, which negatively regulates CCaMK by stabilizing the inactive state of the protein. By contrast, calcium-dependent CaM binding overrides the effects of autophosphorylation and activates the protein. The differential calcium binding affinities of the EF-hand domains compared with those of CaM suggest that CCaMK is maintained in the inactive state at basal calcium concentrations and is activated via CaM binding during calcium oscillations. This work provides a model for decoding calcium oscillations that uses differential calcium binding affinities to create a robust molecular switch that is responsive to calcium concentrations associated with both the basal state and with oscillations.     

Effects of Caregiver-Implemented Aggression Reduction Procedure on Problem Behavior of Dogs

Problem behavior of companion animals poses a threat to caregivers, other targets of problem behavior (e.g., strangers, other nonhuman animals), and those animals engaging in problem behavior. This study examined the effects of an aggression reduction procedure (ARP) on dog problem behavior. After a baseline condition showing caregivers were unsuccessful in reducing dog aggression and the behaviors preceding aggression, caregivers were trained to implement a procedure to address dog problem behavior in relatively simple contexts. Generalization programming then was used to target caregiver plan implementation and dog problem behavior in more complex contexts. The ARP effectively reduced dog aggression for all dogs. A slight reduction and increased variability in dog precursor behavior was observed when the ARP was implemented. In addition, caregivers and experts rated the goals, procedures, and effects as acceptable. Implications of these findings are discussed.     

Purification and Separation of A and B Forms of N-Acetyl-β-D-Hexosaminidase from Human Aorta

Human aorta has been shown to possess multiple forms of N-Acetyl-6-D-hexosaminidase (β-2-acetamido-2-deoxy-D-glucoside-acetamido-deoxyglucohydro-lase, EC 3.2, 1.30). The enzyme was separable, by gel electrophoresis, into 2 enzymatically active bands representing A and B forms. By gel electro-focussing, A and B forms were further subdivided into at least 5 and 8 bands, respectively. The B form consisted of 4 bands (B₁) and 4 bands (B₂), which were not inactivated at 50° for 3 hr. (at pH 4.4) in the presence of serum; whereas, the 5 bands found in A form were completely inactivated. All forms of the enzyme were active towards naphthol-AS-BI-N-acetyl-β-D-glucosaminide and the corresponding galactosaminide (about one-eighth of the hydrolysis rate of the former), suggesting each single enzyme acts on both substrates. The N-acetyl-hexosaminidases of bull epididymis, by comparison, were also found to be active towards both substrates and to possess 13 bands having pis more alkaline than those of the B form of the human enzyme, By heat inactivation we found that the aortic enzyme consisted of 51% of A and 49% of B (B₁ + B₂ .). Neuraminidase had no effect on either form of the aortic preparation. Both forms were partially purified and separated by conventional methods. They required BSA for their maximal activity; the A form being more dependent BSA than the B form, With PNP-N-acetyl-β-D-glucosaminide and the corresponding galactosaminide, Km of 1.04 mH and 0.54 mM, respectively, for A form and of 1.74 and 1.48 mM, respectively, for B form were obtained. While the purified B form was stable and did not transform into other species, the purified A form gradually transformed into B form as well as into other new forms during storage at -20°.     

Bone marrow lesion volume reduction is not associated with improvement of other periarticular bone measures: data from the Osteoarthritis Initiative

Introduction

We evaluated the associations between bone marrow lesion (BML) volume change and changes in periarticular bone mineral density (paBMD) as well as subchondral sclerosis to determine whether BML change is associated with other local bone changes.

Methods

The convenience sample comprised participants in the Osteoarthritis Initiative (OAI) with weight-bearing posterior-anterior knee radiographs and magnetic resonance images (MRIs) at the 24- and 48-month visits and dual-energy x-ray absorptiometry (DXA) at the 30-/36-month and 48-month visits. The right knee was assessed unless contraindicated for MRI. We used knee DXA scans to measure medial tibia paBMD and medial/lateral paBMD ratio (M:L paBMD). Knee radiographs were scored for sclerosis (grades 0 to 3) in the medial tibia. Two raters determined BML volume on sagittal fat-suppressed MRI by using a semiautomated segmentation method. To focus on knees with only medial tibia BML changes, knees with lateral tibial BMLs were excluded. Medial tibial BML volume change was classified into three groups: BML regression (lowest quartile of medial tibial BML volume change), no-to-minimal change (middle two quartiles), and BML progression (highest quartile). We used proportional odds logistic regression models to evaluate the association between quartiles of changes in medial paBMD or M:L paBMD ratio, as outcomes, and BML volume change.

Results

The sample (n = 308) included 163 (53%) female subjects, 212 (69%) knees with radiographic osteoarthritis, and participants with a mean age of 63.8 ± 9.3 years and mean body mass index of 29.8 ± 4.7 kg/m². We found an association between greater increases in medial tibia paBMD and BML regression (OR = 1.7 (95% confidence interval (CI) = 1.1 to 2.8)) and a similar trend for BML progression (OR = 1.6 (95% CI = 1.0 to 2.6]). We also detected associations between greater increase in M:L paBMD and BML regression (OR = 1.6 (95% CI = 1.0 to 2.7]) and BML progression (OR = 1.8 (95% CI = 1.1 to 3.0)), although BML regression had borderline statistical significance. The frequency of sclerosis progression in the medial tibia (n = 14) was greater among knees with BML progression or regression compared with knees without BML change (P = 0.01 and P = 0.04, respectively).

Conclusion

BML regression and BML progression are characterized by concurrent increases in paBMD and sclerosis, which are characteristic of increased radiographic osteoarthritis severity. At least during 24 months, BML regression is not representative of improvement in other periarticular bone measures.     

2,2′-Anhydro-4′-Thionucleosides: Precursors for 2′-Azido- and 2′-Chloro-4′-thionucleosides and for a Novel Thiolane to Thietane Rearrangement

Abstract

2,2′-Anhydro-4′-thio-β-and α-nucleosides 9 and 10 have been prepared by an in situ 4-thio-1,2-glycal addition route. They undergo ring-opening by azide or chloride ion to give, after deprotection, the 2′-substituted-4′-thionucleosides 13 and 14, whereas reactions with cyanide or fluoride sources lead to the unsaturated nucleosides 17 or 18, depending upon conditions. An unexpected and clean rearrangement to the thietane 23 occurs on treatment of uracil derivative 20 with DAST.     

Chronic vitamin E deficiency promotes vitamin C deficiency in zebrafish leading to degenerative myopathy and impaired swimming behavior

We hypothesized that zebrafish (Danio rerio) undergoing long-term vitamin E deficiency with marginal vitamin C status would develop myopathy resulting in impaired swimming. Zebrafish were fed for 1 y a defined diet without (E ?) and with (E +) vitamin E (500 mg α-tocopherol/kg diet). For the last 150 days, dietary ascorbic acid concentrations were decreased from 3500 to 50 mg/kg diet and the fish sampled periodically to assess ascorbic acid concentrations. The ascorbic acid depletion curves were faster in the E ? compared with E + fish (P < 0.0001); the estimated half-life of depletion in the E ? fish was 34 days, while in it was 55 days in the E + fish. To assess swimming behavior, zebrafish were monitored individually following a “startle-response” stimulus, using computer and video technology. Muscle histopathology was assessed using hematoxylin and eosin staining on paramedian sections of fixed zebrafish. At study end, E ? fish contained 300-fold less α-tocopherol (p < 0.0001), half the ascorbic acid (p = 0.0001) and 3-fold more malondialdehyde (p = 0.0005) than did E + fish. During the first minute following a tap stimulus (p < 0.05), E + fish swam twice as far as did E ? fish. In the E ? fish, the sluggish behavior was associated with a multifocal, polyphasic, degenerative myopathy of the skeletal muscle. The myopathy severity ranged from scattered acute necrosis to widespread fibrosis and was accompanied by increased anti-hydroxynonenal staining. Thus, vitamin E deficiency in zebrafish causes increased oxidative stress and a secondary depletion of ascorbic acid, resulting in severe damage to muscle tissue and impaired muscle function.     

A new genus of metalmark moths (Lepidoptera,Choreutidae) with Afrotropical and Australasian?distribution

Niveas Rota, new genus, and its two new species, N. agassizi Rota, new species, and N. kone Rota, new species, are described and illustrated. Niveas is assigned to the subfamily Choreutinae based on morphological and molecular data. Niveas agassizi is currently known only from Kenya and only from female specimens. Niveas kone has been found on the Solomon Islands and in Papua New Guinea (PNG). In PNG, larvae of this species have been reared from several species of Ficus (Moraceae). The two species are superficially quite dissimilar from each other. However, they share features in wing pattern and venation, as well as female genitalia, and the molecular data strongly support the monophyly of Niveas.