Effects of algal food quality on sexual reproduction of Daphnia magna

The objective of our study was to investigate sexual reproduction of Daphnia magna associated with mating behaviors and hatching rates, according to different algal food sources. Since a diatom is known to contain more abundant long‐chain poly unsaturated fatty acids (PUFAs), we hypothesized that the diatom‐consuming D. magna would exhibit more successful reproduction rates. Upon the hypothesis, we designed three experiments using two algal species, a green alga (Chlorella vulgaris) and a diatom (Stephanodiscus hantzschii). From the results, we found that the mating frequency and copulation duration increased in the treatment with S. hantzschii, resulting in a significant increase of hatching rates of resting eggs. In the other two repetitive mating strategies (e.g., one female vs. multiple males, and one male vs. multiple females), we found that the hatching rates of resting eggs were greater in the S. hantzschii treatment. In addition to the mating strategy, male body size significantly increased in the diatom treatment, hence average diameter of penis was also statistically different among the treatments (greater diameter in the S. hantzschii treatment). To examine the effect of algal food quality, we estimated quantity of fatty acids in the two algal species. Our result showed that S. hantzschii had a higher proportion of long‐chain PUFAs than C. vulgaris. Furthermore, a stable isotope analysis revealed that carbon and nitrogen originated from S. hantzschii were more assimilated to D. magna. In summary, our study manifested that diatom consumption of D. magna leads to more successful sexual reproduction. We then discussed how the diatom consumption of zooplankton influences food web dynamics in a freshwater ecosystem.     

A group of expressed cDNA sequences from the wheat fungal leaf blotch pathogen, Mycosphaerella graminicola (Septoria tritici)

A group of expressed sequence tags (ESTs) from the wheat fungal pathogen Mycosphaerella graminicola utilizing ammonium as a nitrogen source has been analyzed. Single pass sequences of complementary DNAs from 986 clones were determined. Contig analysis and sequence comparisons allowed 704 unique ESTs (unigenes) to be identified, of which 148 appeared as multiple copies. Searches of the nrdb95 protein database at EMBL using the BLAST2x algorithm revealed 407 (57.8%) sequences that generated high to moderate high scoring pairs with proteins of known and unknown function. The rest of the sequences (297) showed either weak or no similarities to database entries. Among the unigenes with assigned function, 26.7% were involved in primary metabolism and 17.9% were associated with protein and RNA metabolism. Fewer clones were ascribed roles in signal transduction (4.9%), transport and secretion (6.1%), cell structure (3.1%), and cell division (3.6%). Approximately 18.1% of the identities found were to hypothetical or unknown proteins mainly from the yeasts Saccharomyces cerevisiae and Schizosaccaromyces pombe. Comparison of the 297 sequences with no clear function to other fungal ESTs in the public domain revealed 12 sequences that had high to moderate similarity to Neurospora crassa, Emericella (Aspergillus) nidulans, or Magnaporthe grisea sequences.     

A hybrid bovine ß-casein/bGH gene directs transgene expression to the lung and mammary gland of transgenic mice

We investigated spatial and temporal expression of bGH controlled by two different sizes (1.8kb and 15kb) of 5-flanking sequences of the bovine ß-casein in transgenic mice. In the 1.8-kb promoter-containing mice, bGH expression was specifically confined to lung and mammary gland at lactation. While mammary gland expression was highly variable depending on the lines, lung expression was relatively constant with a high level in most lines. Moreover, this dual-tissue specificity of bGH expression was consistently retained in all of the 15kb-promoter-containing mice, although a low ectopic expression was sometimes detected in salivary gland or brain. During mammary gland development in the 1.8-kb promoter-containing mice was mammary gland expression first detected at lactation, following the bovine rather than murine pattern of ß-casein expression. In contrast, lung expression was almost constant regardless of mammary gland developmental state or sex. Therefore, it can be concluded that a combination of the bovine ß-casein promoter and bGH gene directs a distinct dual-tissue specific bGH expression with different regulatory mechanisms between mammary gland and lung and as little as 1.8-kb promoter is sufficient for the proper regulation of the bovine ß-casein gene in mammary gland.     

Effects of (−)-Sesamin on Chronic Stress-Induced Anxiety Disorders in Mice

This study investigated the effects of (?)-sesamin on chronic electric footshock (EF) stress-induced anxiety disorders in mice. Mice were treated with (?)-sesamin (25 and 50 mg/kg) orally once a day for 21 days prior to exposure to EF stress (0.6 mA, 1 s every 5 s, 3 min). Mice treated with (?)-sesamin (25 and 50 mg/kg) exhibited less severe decreases in the number of open arm entries and time spent on open arms in the elevated plus-maze test and the distance traveled in the open field test following exposure to chronic EF stress. Similarly, mice treated with (?)-sesamin exhibited significantly less severe decreases in brain levels of dopamine, norepinephrine, and serotonin following exposure to chronic EF stress. Increases in serum levels of corticosterone and expression of c-Fos were also less pronounced in mice treated with (?)-sesamin (25 and 50 mg/kg). These results suggest that (?)-sesamin may protect against the effects of chronic EF stress-induced anxiety disorders by modulating dopamine, norepinephrine, and serotonin levels, c-Fos expression, and corticosterone levels.     

Discovery and structure-based design of 4,6-diaminonicotinamides as potent and selective IRAK4 inhibitors

The identification of small molecule inhibitors of IRAK4 for the treatment of autoimmune diseases has been an area of intense research. We discovered novel 4,6-diaminonicotinamides which potently inhibit IRAK4. Optimization efforts were aided by X-ray crystal structures of inhibitors bound to IRAK4. Structure activity relationship (SAR) studies led to the identification of compound 29 which exhibited sub-micromolar potency in a LTA stimulated cellular assay.     

Toosendanin,a novel potent vacuolar-type H+-translocating ATPase inhibitor,sensitizes cancer cells to chemotherapy by blocking protective autophagy

Macroautophagy/autophagy is the process of self-digestion through the lysosomes; it disassembles unnecessary or dysfunctional long-lived proteins and damaged organelles for the recycling of biomacromolecules. Unfortunately, cancer cells can hijack this mechanism to survive under metabolic stress or develop drug resistance during chemotherapy. Increasing evidence indicates that the combination of autophagy inhibition and chemotherapy is a promising cancer treatment strategy. However, effective autophagy inhibitors with satisfied potency, bioavailability, and clearly-defined drug targets are still rare. Here, we report the identification of a potent autophagy inhibitor toosendanin which can effectively block autophagosome maturation, causing the accumulation of autophagy substrates in multiple cancer cells. Toosendanin did not inhibit the fusion process between autophagosome and lysosome but elevated lysosomal pH and impaired lysosomal enzymes activity. Using rat liver lysosome fraction and purified yeast V-ATPase, we found that toosendanin directly inhibited V-ATPase activity. By applying cellular thermal shift assay (CETSA), immunoprecipitation-coupled LC-MS/MS analysis, and biotin-toosendanin pull-down assay, we confirmed the direct binding between toosendanin and V-ATPase. Furthermore, toosendanin blocked chemotherapy-induced protective autophagy in cultured cancer cells and xenograft tumor tissues to significantly enhance anti-cancer activity. These results suggest that toosendanin has the potential to be developed into an anti-cancer drug by blocking chemotherapy-induced protective autophagy.     

Prevalence and Intensity of Opisthorchis viverrini Metacercarial Infection in Fish from Phnom Penh,Takeo, and Kandal Provinces,Cambodia

The prevalence and intensity of Opisthorchis viverrini metacercariae (OvMc) were investigated in fish from 3 southern administrative regions along the Mekong River in Cambodia, i.e., Phnom Penh, Takeo, and Kandal Provinces from 2017 to 2020. A total of 295 freshwater fish (24 species) were transported to our laboratory with ice and examined using the artificial digestion method. In Phnom Penh, among 4 fish species positive for OvMc, 9 (23.7%) of 38 specimens examined were infected, and their intensity of infection averaged 4.3 metacercariae per infected fish. In Takeo Province, among 10 fish species positive for OvMc, 24 (38.1%) out of 63 fish examined were infected, and their intensity of infection was av. 14.4 metacercariae per infected fish. In particular, all of 3 Osteochilus schlegelii fish examined were infected, and their infection intensity was high, 34.7 metacercariae per fish. In Kandal Province, among 6 fish species positive for OvMc, 46 (90.2%) out of 51 specimens examined were infected, and their infection intensity was 24.0 metacercaraie per infected fish. All fish of Systomus orphoides (n=17), Barbonymus altus (n=14), and Rasbora aurotaenia (n=2) were infected, and their intensity of infection averaged 37.7, 21.6, and 18.5 metacercariae per fish, respectively. Metacercariae of Haplochis yokogawai, Haplorchis taichui, and Centrocestus formosanus were detected in fish from Takeo and Kandal Provinces. From these results, it has been confirmed that a variety of fish species from Phnom Penh, Takeo, and Kandal Provinces are commonly infected with OvMc, and preventive measures to avoid human O. viverrini infection should be performed in Cambodia.     

Chronic alcohol consumption potentiates the development of diabetes through pancreatic β-cell dysfunction

Chronic ethanol consumption is well established as a major risk factor for type-2 diabetes(T2D), which is evidenced by impaired glucose metabolism and insulin resistance. However, the relationships between alcoholconsumption and the development of T2 D remain controversial. In particular, the direct effects of ethanol consumption on proliferation of pancreatic β-cell and the exact mechanisms associated with ethanolmediated β-cell dysfunction and apoptosis remain elusive. Although alcoholism and alcohol consumption are prevalent and represent crucial public health problems worldwide, many people believe that low-tomoderate ethanol consumption may protect against T2 D and cardiovascular diseases. However, the J- or U-shaped curves obtained from cross-sectional and large prospective studies have not fully explained the relationship between alcohol consumption and T2 D. This review provides evidence for the harmful effects of chronic ethanol consumption on the progressive development of T2 D, particularly with respect to pancreatic β-cell mass and function in association with insulin synthesis and secretion. This review also discusses a conceptual framework for how ethanolproduced peroxynitrite contributes to pancreatic β-cell dysfunction and metabolic syndrome.     

Three Years' Experience with Bypass Cannulae for Chronic Hemodialysis

In 14 patients over the past three years, “bypass” cannulae have been inserted to relieve obstruction in cannulae used for chronic hemodialyses. Experience with these patients has prompted changes resulting in improved technique.Clotting was the major cause of cannulae failure and infection was the second most important cause. Other causes of failure included: venous atheroma, cannulae extrusion, aneurysms of the vessel at the cannulae tips, obstructive vegetation on the vessel wall, calcium deposits on the vessel wall, and thrombi on the vein walls.The mean survival time was improved from 1.9 months in 1963-1964 to over 9.0 months in 1965-1966. The longest surviving cannula set was two years and the shortest one week.It is considered that the most important factors contributing to increased cannula survival are improved cannula care by patients and staff, the use of angiography for accurate diagnosis, and prompt anticoagulation if atheromatous stenosis of the venous component is encountered.