A Broad-Specificity Chitinase from Penicillium oxalicum k10 Exhibits Antifungal Activity and Biodegradation Properties of Chitin.

Penicillium oxalicum k10 isolated from soil revealed the hydrolyzing ability of shrimp chitin and antifungal activity against Sclerotinia sclerotiorum. The k10 chitinase was produced from a powder chitin-containing medium and purified by ammonium sulfate precipitation and column chromatography. The purified chitinase showed maximal activity toward colloidal chitin at pH 5 and 40 °C. The enzymatic activity was enhanced by potassium and zinc, and it was inhibited by silver, iron, and copper. The chitinase could convert colloidal chitin to N-acetylglucosamine (GlcNAc), (GlcNAc)2, and (GlcNAc)3, showing that this enzyme had endocleavage and exocleavage activities. In addition, the chitinase prevented the mycelial growth of the phytopathogenic fungi S. sclerotiorum and Mucor circinelloides. These results indicate that k10 is a potential candidate for producing chitinase that could be useful for generating chitooligosaccharides from chitinous waste and functions as a fungicide.

Association Between Dietary Iron Intake and Serum Ferritin and Severe Headache or Migraine.

Background: Dietary iron intake and serum ferritin in relation to severe headache or migraine remain largely unknown. Therefore, we investigated the associations between dietary iron intake and serum ferritin with severe headache or migraine among American adults. Methods: This cross-sectional study included 7,880 adults (≥20 years) from the National Health and Nutrition Examination Surveys (NHANES) of America from 1999 to 2004. We performed multivariable logistic regression and restricted cubic spline (RCS) regression to assess the association of dietary iron and serum ferritin with severe headache or migraine. Results: Most women aged 20-50 years consumed less dietary iron than their recommended dietary allowances. Dietary iron intake was inversely associated with severe headache or migraine in women aged 20-50 years. For women over 50 years, serum ferritin was negatively associated with severe headache or migraine. For men, there was no significant relationship between dietary iron and serum ferritin, and severe headache or migraine. Conclusions: Dietary iron intake has different effects on migraine in women of different ages, and this different effect may be due to age-related menstrual changes. Women aged 20-50 years should have a higher awareness of RDA and increase their dietary iron intake if needed, which may play an important role in preventing severe headache or migraine. Higher serum ferritin levels in women aged 50 and above may have a protective effect against migraine.

Dietary Intake of Calcium and Magnesium in Relation to Severe Headache or Migraine.

Background: Migraine is a common neurological disorder and is affected by nutrients. Calcium and magnesium are essential minerals that play an important role in nerve function. So we investigated the association between dietary calcium and magnesium and migraine. Methods: We extracted 10,798 adults from the National Health and Nutrition Examination Surveys (NHANES) of America in 1999 to 2004. We classified patients who reported having severe headache or migraine as having possible migraine. Multivariable logistic regression and restricted cubic spline regression were conducted to determine the association between dietary calcium and magnesium and migraine. Results: We found that the adjusted ORs of the association between dietary calcium and magnesium and migraine for comparing the highest quintile intake with the lowest quintile intake were 0.77 (95% CI: 0.63-0.93, P = 0.008) and 0.69 (95% CI: 0.55-0.86, P = 0.001), respectively. For women, the adjusted ORs of dietary calcium and magnesium were 0.72 (95% CI: 0.56-0.93, P = 0.009) and 0.62 (95% CI: 0.47-0.83, P = 0.001), respectively. For men, the adjusted OR was 0.71 (95% CI: 0.52-0.97, P = 0.028) comparing the highest and the lowest quintile of calcium intake, but there was no statistically significant association between dietary magnesium intake and migraine. Joint analyses showed that the OR in the high-calcium and high-magnesium group was 0.74 (95% CI: 0.60-0.92, P = 0.006) compared with the low-calcium and low-magnesium group in women. Conclusions: High dietary intake of calcium and magnesium, independently or in combination, were inversely associated with migraine in women. For men, high dietary calcium was negatively related to migraine, but magnesium was not associated with migraine.

MicroRNA-181a promotes proliferation and inhibits apoptosis by suppressing CFIm25 in osteosarcoma.

MicroRNA-181a (miR-181a) is upregulated in osteosarcoma, and its overexpression promotes the proliferation and inhibits the apoptosis of osteosarcoma cells. However, the mechanism of miR­181a as an oncogene remains to be fully elucidated in osteosarcoma. Cleavage factor (CF) Im25 links alternative polyadenylation to glioblastoma tumor suppression, however, its role in osteosarcoma has not been reported. In the present study, it was confirmed that the expression of miR­181a was upregulated in osteosarcoma, and that silencing miR­181a inhibited the proliferation and promoted the apoptosis of osteosarcoma cells. miRNAs are short non­coding RNAs, which regulate target mRNAs by binding predominantly to the 3'untranslated region (3'UTR), inducing either translational repression or degradation of the target. In the present study, target genes of miR­181a were screened using miRanda, which is a commonly used prediction algorithm. It was found that miR­181a targeted the 3'UTR of CFIm25 mRNA. Subsequent experiments confirmed that miR­181a downregulated the expression of CFIm25 in osteosarcoma cells. Finally, it was demonstrated that the CFIm25 protein was also downregulated in osteosarcoma tissues, and inhibited the proliferation and promoted the apoptosis of the cells. Elucidating the roles of miR­181a and CFIm25 in osteosarcoma not only assists in further understanding the pathogenesis and progression of this disease, but also offers novel targets for effective therapies.

Recombinant expression of chitosanase from Bacillus subtilis HD145 in Pichia pastoris.

A chitosanase-producing bacterium, Bacillus subtilis HD145 CCTCC AB 2010353, was isolated from a soil sample. The gene (csn) encoding chitosanase was cloned, sequenced, and expressed in the Pichia pastoris strain as a soluble and active form. Its expression level could be as high as 800 mg/L, and enzymatic activity reached approximately 9000 U/mg. The optimum pH and temperature were 5.5 and 50 °C, respectively. The recombinant protein was partially glycosylated. Its half lives at temperatures of 50 and 60 °C were 26 h and 23 min, respectively. Enzymatic activity was increased with an increasing degree of deacetylation of chitosan. The enzymatic productions of chitooligosaccharides from chitosans of various deacetylation degrees mainly ranged from chitobiose to chitopentamer.