Cellulase production and efficient saccharification of biomass by a new mutant Trichoderma afroharzianum MEA-12

Background Cellulase plays a key role in converting cellulosic biomass into fermentable sugar to produce chemicals and fuels, which is generally produced by filamentous fungi. However, most of the filamentous fungi obtained by natural breeding have low secretory capacity in cellulase production, which are far from meeting the requirements of industrial production. Random mutagenesis combined with adaptive laboratory evolution (ALE) strategy is an effective method to increase the production of fungal enzymes. Results This study obtained a mutant of Trichoderma afroharzianum by exposures to N-methyl-N’-nitro-N-nitrosoguanidine (MNNG), Ethyl Methanesulfonate (EMS), Atmospheric and Room Temperature Plasma (ARTP) and ALE with high sugar stress. The T. afroharzianum mutant MEA-12 produced 0.60, 5.47, 0.31 and 2.17 IU/mL FPase, CMCase, pNPCase and pNPGase, respectively. These levels were 4.33, 6.37, 4.92 and 4.15 times higher than those of the parental strain, respectively. Also, it was found that T. afroharzianum had the same carbon catabolite repression (CCR) effect as other Trichoderma in liquid submerged fermentation. In contrast, the mutant MEA-12 can tolerate the inhibition of glucose (up to 20 mM) without affecting enzyme production under inducing conditions. Interestingly, crude enzyme from MEA-12 showed high enzymatic hydrolysis efficiency against three different biomasses (cornstalk, bamboo and reed), when combined with cellulase from T. reesei Rut-C30. In addition, the factors that improved cellulase production by MEA-12 were clarified. Conclusions Overall, compound mutagenesis combined with ALE effectively increased the production of fungal cellulase. A super-producing mutant MEA-12 was obtained, and its cellulase could hydrolyze common biomasses efficiently, in combination with enzymes derived from model strain T. reesei, which provides a new choice for processing of bioresources in the future.

Reduction in GLP-1 secretory capacity may be a novel independent risk factor of coronary artery stenosis

Multiple factors regulate glucagon-like peptide-1 (GLP-1) secretion, but a group of apparently healthy subjects showed blunted responses of GLP-1 secretion in our previous study. In this study, we examined whether the reduction in GLP-1 secretory capacity is associated with increased extent of coronary artery stenosis in non-diabetic patients. Non-diabetic patients who were admitted for coronary angiography without a history of coronary interventions were enrolled. Coronary artery stenosis was quantified by Gensini score (GS), and GS ≥ 10 was used as an outcome variable based on its predictive value for cardiovascular events. The patients (mean age, 66.5 ± 8.8 years; 71% males, n = 173) underwent oral 75 g-glucose tolerant tests for determination of glucose, insulin and active GLP-1 levels. The area under the curve of plasma active GLP-1 (AUC-GLP-1) was determined as an index of GLP-1 secretory capacity. AUC-GLP-1 was not correlated with fasting glucose, AUC-glucose, serum lipids or indices of insulin sensitivity. In multivariate logistic regression analysis for GS ≥ 10, AUC-GLP-1 < median, age and hypertension were selected as explanatory variables, though fasting GLP-1 level was not selected. The findings suggest that reduction in GLP-1 secretory capacity is a novel independent risk factor of coronary stenosis.

Lifestyle is associated with thyroid function in subclinical hypothyroidism: a cross-sectional study

Background Few studies have focused on the association between lifestyle and subclinical hypothyroidism (SCH). The purpose of this study was to investigate the association between lifestyle and thyroid function in SCH. Methods This study was a part of a community-based and cross-sectional study, the Epidemiological Survey of Thyroid Diseases in Fujian Province, China. A total of 159 participants with SCH (81 males and 78 females) and 159 euthyroid (87 males and 72 females) participants without any missing data were included in the analysis. General information and lifestyle information including sleep, exercise, diet and smoking habits of the participants was collected by questionnaire and Pittsburgh sleep quality index scale (PSQI) was collected. Thyroid stimulating hormone (TSH), free thyroxine (FT4), thyroid peroxidase antibody (TPOAb), thyroid globulin antibody (TgAb) and urine iodine concentration (UIC) were tested. Thyroid homeostasis parameter thyroid’ s secretory capacity (SPINA-GT), Jostel’s TSH index (TSHI), thyrotroph T4 sensitivity index (TTSI) were calculated. Logistic regression and multiple linear regression were performed to assess associations. Results Compared with euthyroid subjects, patients with SCH were more likely to have poor overall sleep quality (15.1 vs.25.8 %, P = 0.018) and l less likely to stay up late on weekdays (54.7 vs. 23.9 % P < 0.001). In SCH group, exercise was the influencing factor of TSH (β= -0.224, P = 0.004), thyroid secretory capacity (β = 0.244, P = 0.006) and thyrotropin resistance (β = 0.206, P = 0.009). Iodine excess was the influencing factor of thyroid secretory capacity (β = 0.209, P = 0.001) and pituitary thyroid stimulating function (β = 0.167, P = 0.034). Smoking was the influencing factor of pituitary thyroid stimulating function (β = 0.161, P = 0.040). Staying up late on weekends was the influencing factor of thyroid secretory capacity (β = 0.151, P = 0.047). After adjusting for possible confounders, logistic regression showed that those with poor overall sleep quality assessed by PSQI and iodine excess had an increased risk of SCH (OR 2.159, 95 %CI 1.186–3.928, P = 0.012 and OR 2.119, 95 %CI 1.008–4.456, P = 0.048, respectively). Conclusions Lifestyle including sleep, smoking, diet and exercise was closely related to thyroid function especially thyroid homeostasis in SCH.

Analysis of the formation of dysglycemia in the substantiation of early pathogenetic therapy of diabetes mellitus

Introduction. To control carbohydrate metabolism disorders (CMD), which are closely related to the effect on the prognosis of cardiovascular diseases (CVD), their early, pathogenetically substantiated and prognosis-oriented therapy is required with a view to positive metabolic memory. The choice of drugs is based on the analysis of the formation of pre-nosological CMD - variants of prediabetes. The indices of the homeostatic model HOMA and the TyG family are most often used to assess the main links in the pathogenesis of CMD, IR and the secretory capacity of β-cells.Objective: to assess the basic pathogenetic links in prenosological CMD in comparison with type 2 diabetes mellitus (DM2) using a cohort of postmenopausal women: parameters of IR and secretory capacity of β-cells according to the TyG and HOMA-2 indices. Materials and methods. The examined 94 postmenopausal women 58.0 (53.0; 63.0) years old were divided into groups by history and HbA1c levels (%). Group 1 consisted of patients with T2DM (7.20: 6.60; 7.98) with a duration of 4.0 (2.0; 7.0) years; women with two-fold fasting normoglycemia without a history of CMD were classified according to their HbA1c levels into group 2 (prediabetes) and 3 (without CMD) twice: according to WHO criteria - 6.15 (6.03; 6.30) and 5.45 (5.20; 5.80); and ADA - 6.00 (5.80; 6.23) and 5.35 (5.05; 5.40), respectively. The indices TyG, HOMA2-IR, HOMA2-%S, and HOMA2-%B were determined (based on C-peptide calculations).Results and discussion. The performed analysis confirms the contribution of IR/insulin sensitivity to the progression of CMD with the participation of the phenomenon of lipoglucotoxicity at the prenosological stage of their formation, starting with HbA1c ≥ 5.7% levels. The inadequate secretory response of β-cells reflects an early decline in their functional abilities even at the stage of prediabetes. This limits the effectiveness of the classical stepwise scheme for intensifying glucose-lowering therapy with a T2DM duration of less than 10 years.Conclusions. Along with the timely diagnosis of dysglycemia, to control the cardiometabolic risk, it is advisable to use drug combinations early in terms of their effect on the key links in the pathogenesis of CMD: insulin resistance and β-cell dysfunction. Pioglitazone has been substantiated as an insulin sensitizer, which has a proven effect on the regression of early CMD and a decrease in the risk of cardiovascular events. In order to eliminate incretin dysfunction, which is closely related to the adequacy of the secretory capabilities of β-cells to the needs of impaired glucose homeostasis, a rational combination with an inhibitor of dipeptidyl peptidase-4.

Effects of the Rate of Impaired Insulin Secretion on Bone Mineral Density in Type 1 Diabetes

Background: Type 1 Diabetes mellitus (T1DM) is a well-known condition associated with low bone mineral density (BMD) and bone fracture, in which one of the risk factor is impaired endogenous insulin secretion. However, the association between the rate of impaired insulin secretory capacity in T1DM and BMD remains to be elucidated. Objective: To clarify the effect of the rate of impaired insulin secretion on BMD in T1DM. Patients and Methods: This a retrospective single-center cross-sectional study, in which consecutive one-hundred seventy Japanese patients with T1DM at Kobe University Hospital were registered. According to the diagnostic criteria of The Japan Diabetes Society, patients were stratified into three subtypes; acute-onset (AO) (n =51, male 25%, 39 ± 15 years), slowly-progressive (SP) (n =37, male 37%, 57 ± 14 years), and fulminant (F) (n =12, male 33%, 51 ± 15 years) mainly by insulin secretory capacity at onset of T1DM. Lumbar spine (LS) and femoral neck (FN) BMD Z-score between three groups were evaluated. Results: The LS BMD is lower in AO than SP (p =0.03), while no differences were observed compared to F (SP/AO/F; 0.38 ± 1.08/-0.25 ± 0.96/-0.35 ± 1.01). The FN BMD also tended to be lower in AO than in SP (p =0.08) and in F (p =1.00) (SP/AO/F;0.03 ± 1.01/-0.44 ± 0.96/-0.35 ± 0.70). To identify the factors associated with decreased BMD, the multivariate regression analysis was performed using AO and SP. The LS BMD was associated with the pathogenic group (p =0.01). Since a negative correlation was seen between durations and CPR both in AO and SP group (p &lt;0.01, p &lt;0.01), we divided these subjects into following 5 groups; 1 to 4, 5 to 9, 10 to 14, 15 to 19, and more than 20 years. In these groups, the CPR was lower in AO than in SP in 1 to 4 years (p &lt;0.01). Intriguingly, LS BMD was started to decline in 5 to 9 years (p =0.03) and was still continued in 10 to 14 years (p =0.01). In FN, BMD was started to decline in 10 to 14 years (p =0.01), suggesting the BMD decline followed by impaired insulin secretion. However, the difference of both BMD and CPR between AO and SP groups were not seen in more than 15 years group, indicating this tangent BMD difference is link to the difference of insulin secretion. Conclusions: This study firstly showed that pathogenic subtypes of T1DM differently affected on BMD. A detailed examination of each disease period showed that BMD continued to decrease as impaired insulin secretion.