PDGF-AA activates AKT and ERK signaling for testicular interstitial Leydig cell growth via primary cilia.

Testes control the development of male reproductive system. The testicular interstitial Leydig cells (Leydig cells) synthesize testosterone for promoting spermatogenesis and secondary sexual characteristics. Type A platelet-derived growth factor (PDGF-AA) is one of the most important growth factors in regulating Leydig cell growth and function.

[Comparison of Bacterial Community Structure in Soil Aggregates Between Natural Karst Wetland and Paddy Field].

Studying the impact of land-use changes in wetland systems on the community structure of bacteria in soil aggregates can provide a theoretical basis for elucidating the impact mechanisms of the stability of wetland soil aggregates. The soil samples (0-20 cm) were collected from a natural wetland and paddy field in the Huixian karst wetland. The bacterial community structure in soil aggregates (macroaggregates 0.

[Comparison of Bacterial Community Structure and Functional Groups of Paddy Soil Aggregates Between Karst and Non-karst Areas].

Studying the similarities and differences in microbial community structure and functional groups in soil aggregates between karst areas (KA) and non-karst areas (NKA) can provide a theoretical basis for revealing the interaction mechanism between soil organic microorganisms and soil aggregate structure stability in KA. The surface soils (0-20 mm) were collected from paddy fields both in KA and NKA. The aggregates were divided into macro-aggregates (Mac, 0.

[Investigation of Soil Fungal Communities and Functionalities within Karst Paddy Fields].

Fungi are important drivers of soil biogeochemical cycles. However, the characteristics of fungal community structures and functional groups within karst area (KA) soils remain understudied. Top soil samples were collected from paddy fields within a KA and non-karst area (NKA) containing red soil, in the Maocun karst experimental site of Guilin.

Genotoxic stress-activated DNA-PK-p53 cascade and autophagy cooperatively induce ciliogenesis to maintain the DNA damage response.

The DNA-PK maintains cell survival when DNA damage occurs. In addition, aberrant activation of the DNA-PK induces centrosome amplification, suggesting additional roles for this kinase. Here, we showed that the DNA-PK-p53 cascade induced primary cilia formation (ciliogenesis), thus maintaining the DNA damage response under genotoxic stress.

Intravoxel incoherent motion derived liver perfusion/diffusion readouts can be reliable biomarker for the detection of viral hepatitis B induced liver fibrosis.

Background: Recent two studies reported that intravoxel incoherent motion (IVIM) analysis can separate healthy livers and viral hepatitis B (VHB) induced liver fibrosis. However, in these two studies the starting value for bi-exponential decay analysis was =10 and 15 s/mm respectively. The current study has two primary aims.

Heterocyclyl tetracyclines. 2. 7-Methoxy-8-pyrrolidinyltetracyclines: discovery of TP-2758, a potent, orally efficacious antimicrobial against Gram-negative pathogens.

A convergent total synthesis platform led to the discovery of TP-2758 from a series of novel 7-methoxy-8-heterocyclyl tetracycline analogs. TP-2758 demonstrated high in vitro potency against key Gram-negative pathogens including extended spectrum β-lactamases- and carbapenemase-producing Enterobacteriaceae and Acinetobacter spp. strains.

Heterocyclyl Tetracyclines. 1. 7-Trifluoromethyl-8-Pyrrolidinyltetracyclines: Potent, Broad Spectrum Antibacterial Agents with Enhanced Activity against Pseudomonas aeruginosa.

Utilizing a total synthesis approach, the first 8-heterocyclyltetracyclines were designed, synthesized, and evaluated against panels of tetracycline- and multidrug-resistant Gram-positive and Gram-negative pathogens. Several compounds with balanced, highly potent in vitro activity against a broad range of bacterial isolates were identified through structure-activity relationships (SAR) studies. One compound demonstrated the best antibacterial activity against Pseudomonas aeruginosa both in vitro and in vivo for tetracyclines reported to date.

Design, Synthesis, and Biological Evaluation of Hexacyclic Tetracyclines as Potent, Broad Spectrum Antibacterial Agents.

A series of novel hexacyclic tetracycline analogues ("hexacyclines") was designed, synthesized, and evaluated for antibacterial activity against a wide range of clinically important bacteria isolates, including multidrug-resistant, Gram-negative pathogens. Valuable structure-activity relationships were identified, and several hexacyclines displayed potent, broad spectrum antibacterial activity, including promising anti-Pseudomonas aeruginosa activity in vitro and in vivo.

Synthesis and biological evaluation of 8-aminomethyltetracycline derivatives as novel antibacterial agents.

The C-8 position of the tetracyclines has been largely underexplored because of limitations in traditional semisynthetic techniques. Employing a total synthetic approach allowed for modifications at the C-7 and C-8 positions, enabling the generation of structure-activity relationships for overcoming the two most common tetracycline bacterial-resistance mechanisms: ribosomal protection (tet(M)) and efflux (tet(A)). Ultimately, several compounds were identified with balanced activity against both Gram-positive and Gram-negative bacteria, including pathogens bearing both types of tetracycline-resistance mechanisms.

Fluorocyclines. 2. Optimization of the C-9 side-chain for antibacterial activity and oral efficacy.

Utilizing a fully synthetic route to tetracycline analogues, the C-9 side-chain of the fluorocyclines was optimized for both antibacterial activity and oral efficacy. Compounds were identified that overcome both efflux (tet(K), tet(A)) and ribosomal protection (tet(M)) tetracycline-resistance mechanisms and are active against Gram-positive and Gram-negative organisms. A murine systemic infection model was used as an oral efficacy screen to rapidly identify compounds with oral bioavailability.

Fluorocyclines. 1. 7-fluoro-9-pyrrolidinoacetamido-6-demethyl-6-deoxytetracycline: a potent, broad spectrum antibacterial agent.

This and the accompanying report (DOI: 10.1021/jm201467r ) describe the design, synthesis, and evaluation of a new generation of tetracycline antibacterial agents, 7-fluoro-9-substituted-6-demethyl-6-deoxytetracyclines ("fluorocyclines"), accessible through a recently developed total synthesis approach. These fluorocyclines possess potent antibacterial activities against multidrug resistant (MDR) Gram-positive and Gram-negative pathogens.

Synthesis and antibacterial activity of pentacyclines: a novel class of tetracycline analogs.

Employing a highly efficient total synthesis approach, we synthesized and evaluated for antibacterial activity diverse and novel pentacycline analogs with systematic variations at C7, C8, C9, and C10. Certain substitution groups, as well as substitution patterns at various positions, were found to be preferred for increased antibacterial activity. A number of pentacycline analogs displayed potent activity in vitro and in vivo, especially against Gram-positive organisms.

8-Azatetracyclines: synthesis and evaluation of a novel class of tetracycline antibacterial agents.

A novel series of fully synthetic 8-azatetracyclines was prepared and evaluated for antibacterial activity. Compounds were identified that overcome both efflux (tet(K)) and ribosomal protection (tet(M)) tetracycline resistance mechanisms and are active against Gram-positive and Gram-negative organisms. Two compounds were identified that exhibit comparable efficacy to marketed tetracyclines in in vivo models of bacterial infection.

Design and synthesis of thiazole-5-hydroxamic acids as novel histone deacetylase inhibitors.

We have designed and synthesized a series of structurally novel hydroxamic acid-based histone deacetylase (HDAC) inhibitors characterized by a zinc chelating head group attached directly to a thiazole ring. The thiazole ring connects to a piperazine spacer, which is capped with a sulfonamide group. These novel molecules potently inhibit an HDAC enzyme mixture derived from HeLa cervical carcinoma cells and show potent antiproliferative activity against the breast cancer cell line MCF7.

Combinatorial approach to identification of tyrphostin inhibitors of cytokine signaling.

Aberrant or deregulated activity of certain cellular kinases has been shown to cause certain malignancies and other disorders. The tyrphostin molecule AG490 inhibits the action of the janus kinases JAK2 and JAK3. JAK2 is an indispensable molecule for transducing the signals conveyed by a large number of cytokines including IL-3 while JAK3 is essential for signaling by a smaller number of cytokines including IL-7.

Photoaffinity labeling identifies the substrate-binding site of mammalian squalene epoxidase.

Squalene epoxidase (SE) catalyzes the conversion of squalene to (3S)-2,3-oxidosqualene. Photolabeling and site-directed mutagenesis were performed on recombinant rat SE (rrSE) in order to identify the location of the substrate-binding site and the roles of key residues in catalysis. Truncated 50-kDa rrSE was purified and photoaffinity labeled by competitive SE inhibitor (Ki=18.

Solid-phase synthesis of alkyl aryl ethers via the Ullmann condensation.

Alkyl aryl ether formation is a frequently employed reaction in organic synthesis. Ullmann condensation is an alternative method to the widely used Mitsunobu reaction and is very useful in situations where application of the Mitsunobu reaction is limited. By application of this reaction to solid-phase synthesis of a series of alkyl aryl ethers, reaction conditions (catalyst, solvent, temperature, time, etc.