Immunohistochemical evidence: testicular and scented glandular androgen synthesis in muskrats (Ondatra zibethicus) during the breeding season

In order to elucidate the relationship between androgens and the function of the muskrat (Ondatra zibethicus) scented glands during the breeding season, we investigated immunolocalization of steroidogenic enzymes P450scc, 3βHSD and P450c17 in the muskrat testes and scented glands. Nine adult muskrats were obtained in March (n=3), May (n=3) and July (n=3) 2010. Steroidogenic enzymes were immunolocalized using polyclonal antisera raised against bovine adrenal P450scc, human placental 3βHSD and porcine testicular P450c17. Histologically, all types of spermatogenic cells including mature-phase spermatozoa in seminiferous tubules were observed in all testes. Glandular cells, interstitial cells, epithelial cells and excretory tubules were identified in scented glands during the breeding season. P450scc, 3βHSD and P450c17 were only identified in Leydig cells during the breeding season; P450scc and P450c17 were observed in glandular cells of scented glands, however, 3βHSD was not found in scented glands during the breeding season. These novel findings provide the first evidence showing that scented glands of the muskrats are capable of locally synthesizing androgens and androgens acting via an endocrine, autocrine or paracrine manner may play an important role in scented gland function during the breeding season.

Con A-binding protein Zn-α2-glycoprotein on human sperm membrane is related to acrosome reaction and sperm fertility

Fertilization, the recognition and fusion between spermatozoa and oocyte, involves various molecules on the spermatozoa and oocyte membranes. Concanavalin A (ConA)-binding proteins may be one of the molecules involved in mammal spermatozoa fertilization; however, their structure and function remain largely unknown. Here, we initially identified a ConA-binding protein, Zn-α2-glycoprotein (ZAG), involved in regulating the acrosome reaction (AR) of human spermatozoa. ZAG is localized on the pre-equatorial region covering the acrosome, neck and tail (some parts of middle piece and principal piece respectively) regions of the acrosome intact human spermatozoa, and disappears in the acrosomal region of the acrosome-reacted spermatozoa. Polyclonal antibodies against human recombinant ZAG significantly reduced the AR and sperm capability binding to human zona pellucida or penetration into zona-free hamster oocytes. Furthermore, assessment of the signaling pathways regulated by ZAG revealed that ZAG affects sperm AR through both the cAMP/PKA and PKC pathways. These results indicate that ZAG, which is present on the human sperm membrane, plays a critical role in the AR and subsequently, may be involved in sperm fertility.

The preventive effects of pulsed electromagnetic fields on diabetic bone loss in streptozotocin-treated rats

The present study was the first report demonstrating that pulsed electromagnetic field (PEMF) could partially prevent bone strength and architecture deterioration and improve the impaired bone formation in streptozotocin-induced diabetic rats. The findings indicated that PEMF might become a potential additive method for inhibiting diabetic osteopenia or osteoporosis.

INTRODUCTION

Diabetes mellitus (DM) can cause various musculoskeletal abnormalities. Optimal therapeutic methods for diabetic bone complication are still lacking. It is essential to develop more effective and safe therapeutic methods for diabetic bone disorders. Pulsed electromagnetic field (PEMF) as an alternative noninvasive method has proven to be effective for treating fracture healing and osteoporosis in non-diabetic conditions. However, the issue about the therapeutic effects of PEMF on diabetic bone complication has not been previously investigated.

METHODS

We herein systematically evaluated the preventive effects of PEMF on diabetic bone loss in streptozotocin-treated rats. Two similar experiments were conducted. In each experiment, 16 diabetic and eight non-diabetic rats were equally assigned to the control, DM, and DM + PEMF group. DM + PEMF group was subjected to daily 8-h PEMF exposure for 8 weeks.

RESULTS

In experiment 1, three-point bending test suggested that PEMF improved the biomechanical quality of diabetic bone tissues, evidenced by increased maximum load, stiffness, and energy absorption. Microcomputed tomography analysis demonstrated that DM-induced bone architecture deterioration was partially reversed by PEMF, evidenced by increased Tb.N, Tb.Th, BV/TV, and Conn.D and reduced Tb.Sp and SMI. Serum OC analysis indicated that PEMF partially prevented DM-induced decrease in bone formation. In experiment 2, no significant difference in the bone resorption marker TRACP5b was observed. These biochemical findings were further supported by the dynamic bone histomorphometric parameters BFR/BS and Oc.N/BS.

CONCLUSIONS

The results demonstrated that PEMF could partially prevent DM-induced bone strength and architecture deterioration and improve the impaired bone formation. PEMF might become a potential additive method for inhibiting diabetic osteoporosis.

Dinuclear copper complexes of organic claw: potent inhibition of protein tyrosine phosphatases

Three dinuclear copper complexes of organic claw ligands (2,2',2″,2'''-(5-R-2-hydroxy-1,3-phenylene)bis(methylene)bis(azanetriyl)tetraacetic acid, R=methyl (H(5)L1), chloro (H(5)L2) and bromo (H(5)L3)): [Cu(2)NaL1(H(2)O)(2)] (1), [Cu(2)HL2(H(2)O)(2)] (2), [Cu(2)NaL3(H(2)O)(2)] (3), have been synthesized and characterized by elemental analyses, infrared spectra, thermo-gravimetric analyses, X-ray diffraction analysis, electrospray ionization mass spectra, pH-potentiometric titration, molar conductivity. Their inhibitory effects against human protein tyrosine phosphatase 1B (PTP1B), T cell protein tyrosine phosphatase (TCPTP), Megakaryocyte protein tyrosinephosphatase 2 (PTP-MEG2), srchomology phosphatase 1 (SHP-1) and srchomology phosphatase 2 (SHP-2) are evaluated in vitro. The three copper complexes exhibit potent and almost same inhibition against PTP1B and SHP-1 with IC(50) values ranging from 0.15 to 0.31μM, about 2-fold stronger inhibition than against PTP-MEG2, 10-fold stronger inhibition than against TCPTP, but almost no inhibition against SHP-2. Kinetic analysis indicates that they are reversible competitive inhibitors of PTP1B. Molecular docking analyses confirm the inhibition model. Fluorescence titration studies suggest that the complexes bond to PTP1B with the formation of a 1:1 complex. The results demonstrate that copper complexes that are potent PTPs inhibitors but have different inhibitory effects over different PTPs, may be explored as new practical inhibitors towards individual PTP with some specificity.

Neuroanatomic and behavioral traits for autistic disorders in age-specific restricted index selection mice

The pathogenesis of neurodevelopmental disorders such as autism is believed to be influenced by interactions between genetic and environmental factors, and appropriate animal models are needed to assess the influence of such factors on relevant neurodevelopmental phenotypes. A set of inbred mouse strains (Atchley strains) including A12 (E+L0) and A22 (E-L0) were generated by age-specific restricted index selection from a baseline random-bred ICR mouse population obtained from Harlan Sprague-Dawley [Atchley et al. (1997) Genetics 146(2):629-640; Indianapolis, IN, USA). As compared with the A22 strain, A12 mice had significantly increased early (P0-P10) body weight gain with minimal changes in late (P28-P56) body weight gain. We found that these strains also differed in brain weight, brain volume, cell proliferation, and FGF-2 levels in certain brain regions. Specifically, brain weight and volume were significantly greater in A12 mice than that in A22 mice at P10 and P28. Quantitative analysis of bromodeoxyuridine (BrdU) labeling of proliferating cells showed that the number of BrdU-positive cells in the A12 strain were significantly greater in the frontal cortex and lesser in the dentate gyrus than that in the A22 strain at P28. Western blot revealed that fibroblast growth factors-2 (FGF-2), but not brain-derived neurotrophic factor (BDNF), expression was significantly increased in the frontal cortex of A12 strain at P28. Also, A12 mice exhibited decreased intra-strain social interaction and increased repetitive stereotyped behaviors at P28. Our study suggests that A12 mice may partially mimic the anatomic and behavioral traits of patients with neurodevelopmental disorders such as autism spectrum disorders, and therefore may yield insights into the developmental mechanisms involved in their pathogenesis.

Mononuclear copper(II) complexes with 3,5-substituted-4-salicylidene-amino-3,5-dimethyl-1,2,4-triazole: synthesis, structure and potent inhibition of protein tyrosine phosphatases

Six copper complexes of Schiff base ligands containing 3,5-substituted-4-salicylideneamino-3,5-dimethyl-1,2,4-triazole have been synthesized and well characterized. The structures of complexes 1 and 2 were determined by X-ray crystal analysis. Fluorescence and potentiometric study indicated that in the physiological pH range, one ligand was dissociated from the complexes to form 1:1 mononucleus copper complexes. The complexes potently inhibit protein tyrosine phosphatase 1B (PTP1B), T-cell protein tyrosine phosphatase (TCPTP), megakaryocyte protein tyrosine phosphatase 2 (PTP-MEG2) and Src homology phosphatase 1 (SHP-1) with 3-4 fold selectivity against PTP1B over TCPTP and PTP-MEG2, and 3-9 fold over SHP-1, but display almost no inhibition against Src homology phosphatase 2 (SHP-2). Complex 1 inhibits PTP1B with a competitive model with K(i) of 30 nM. Substitution with small groups at the phenyl of the ligand does not obviously influence the inhibitory ability of the complexes.

Estrogen regulates the expression and activity of epithelial sodium channel in mouse osteoblasts

Estrogen plays an important role in bone metabolism and only high dose can stimulate osteoblast bone formation. However, the underlying mechanisms have not been elucidated. The epithelial sodium channel (ENaC) is a key pathway for sodium transport in epithelia, vascular endothelium, and other tissues; although the expressions of α and γ ENaC mRNA were found in osteoblasts, the regulation of ENaC by estrogen in osteoblasts has not been studied. Our recent data confirmed the ENaC expression in mouse primary osteoblasts by immunocytofluorescence, RT-PCR, western blot, and patch clamp. Furthermore, we found estrogen (10(-5)M) increased the expression of α and γ ENaC subunits at both the mRNA and protein levels in osteoblasts. On the other hand, 17β estradiol (20 nM) increased inward Na+ currents which were inhibited by amiloride. The estrogen dose used in patch clamp is much lower than those of mRNA and protein analysis, which means single cell ENaC electrophoretic mobility is much more sensitive to estrogen than the mRNA and protein production by estrogen stimulation. Our results suggest that estrogen regulates expression and function of ENaC in osteoblasts may provide a new clue that the mechanism of high dose of estrogen influence osteoblast bone formation via ENaC activity.

New phylogenetically distinct cyanophages found in the coastal Yellow Sea by Qingdao

Genetic composition of natural cyanophage population in the coastal Yellow Sea area near Qingdao was investigated using the g20 gene as a genetic marker. Amplification of this gene by PCR yielded sequences, which were cloned and subjected to the restriction fragment length polymorphism (RFLP) analysis. Sixteen clones exhibiting different RFLP patterns were sequenced and analyzed. The sequence analysis indicated a diversity of cyanophages covering sixteen g20 genotypes. Their phylogenetic analysis revealed two distinct phylogenetic groups. One group (7clones) localized with the cyanophage P77 in the cluster III described before. Second group (9 clones) did not localize with any of the cyanophage described so far and was designated as a novel W cluster. The study revealed a genetic diversity of cyanophages in the coastal Yellow Sea and confirmed the genetic differences between cyanophage populations in Western and Eastern Pacific.