Recurrent fruit harvesting reduces seedling density but increases the frequency of clonal reproduction in a tropical tree

Studies on the ecological impacts of non‐timber forest products (NTFP) harvest reveal that plants are often more resilient to fruit and seed harvest than to bark and root harvest. Several studies indicate that sustainable fruit harvesting limits can be set very high (>80% fruit harvesting intensity). For species with clonal and sexual reproduction, understanding how fruit harvest affects clonal reproduction can shed light on the genetic risks and sustainability of NTFP harvest. We studied 18 populations of a gallery forest tree, Pentadesma butyracea (Clusiaceae), to test the impact of fruits harvest, climate and habitat size (gallery forest width) on the frequency of sexual or clonal recruitment in Benin, West Africa. We sampled populations in two ecological regions (Sudanian and Sudano‐Guinean) and in each region, we selected sites with low, moderate and high fruit harvesting intensities. These populations were selected in gallery forests with varying width to sample the natural variation in P. butyracea habitat size. Heavily harvested populations produced significantly less seedlings but had the highest density and proportion of clonal offspring. Our study suggests that for plant species with dual reproductive strategy (via seeds and clonal), fruit harvesting and associated disturbances that come with it can lead to an increase in the proportion of clonal offspring. This raises the issue that excessive fruit harvest by increasing the proportion of clonal offspring to the detriment of seed originated offspring may lead to a reduction in genetic diversity with consequence on harvested species capability to withstand environmental stochasticity.     

Influence of exogenous enzymes on nutrient digestibility, extent of ruminal fermentation as well as milk production and composition in dairy cows

This experiment studied effects of a mixture of exogenous enzymes (ZADO^®) from anaerobic bacteria on ruminal fermentation, feed intake, digestibility, as well as milk production and composition in cows fed total mixed rations (TMRs; 0.7 corn silage and 0.3 of a concentrate mixture). Twenty lactating multiparous Brown Swiss cows (500 ± 12.4 kg live weight) were randomly assigned into two experimental groups of 10 immediately after calving and fed a TMR with or without (CTRL) addition of 40 g/cow/d of enzymes for 12 weeks. Addition of enzymes increased (P<0.05) rumen microbial N synthesis. Intake of dry matter (DM) and organic matter (OM) was positively influenced (P<0.05) by supplementation, and digestibility of all nutrients was higher (P<0.05) in the total tract of supplemented cows, although the magnitude of the improvement varied among nutrients, with the highest improvement in aNDFom and ADFom (418–584 and 401–532 g/kg respectively; P<0.05) than the other nutrients. Supplementation of enzymes also increased (P<0.05) rumen ammonia N and total short chain fatty acid (SCFA) concentrations, and individual SCFA proportions were also altered with an increase in acetate (61.0–64.8 mol/100 mol; P=0.05) before feeding, and acetate and propionate increased 3 h post-feeding (60.0–64.0 and 18.3–20.8 mol/100 mol respectively; P<0.05). Milk and milk protein production was higher (12.8–15.7 and 0.45–0.57 kg/d respectively; P<0.05) for cows fed the ZADO^® supplemented diet. This exogenous enzyme product, supplemented daily to the TMR of cows in early lactation, increased milk production due to positive effects on nutrient intake and digestibility, extent of ruminal fermentation and microbial protein synthesis.     

Mycetoma in the Togolese: An Update from a Single-Center Experience

Background

Mycetoma is a chronic inflammatory process caused either by fungi (eumycetoma) or bacteria (actinomycetoma). In this retrospective study, we report epidemiologic and histopathological data of mycetoma observed in the Lome Hospital, Togo in a 25-year period (1992–2016).

Methodology

This is a retrospective study, over a period of 25 years, to analyze epidemiological and etiological findings of mycetomas seen in the single laboratory of pathological anatomy of the Lomé, Togo.

Results

A total of 61 cases were retrieved from which only 33 cases were included which where clinically and microbiologically confirmed. The mean age of the patients was 29.7?±?1.34 and a sex ratio (M/F) of 1.5. The majority of patients were farmers (n?=?23 cases; 69.7%). Diagnosed etiologic agents were fungal in 24 cases (72.7%) and actinomycotic cases in 9 cases (27.3%). The fungal mycetomas consisted of Madurella mycetomatis (black grains) and Falcifomispora senegaliensis (black grains). The actinomycotic agents were represented by Actinomadura madurae (white grains), Actinomadurae pelletieri (red grains) and Nocardia sp. (yellow grains).

Conclusion

This report represents a single-center study which provides epidemiologic and histopathological data of mycetoma cases in Togo.

     

A comparison of hepatoprotective activities of aminoguanidine and N-acetylcysteine in rat against the toxic damage induced by azathioprine

Azathioprine (AZA) is an important drug used in the therapy of autoimmune system disorders. It induces hepatotoxicity that restricts its use. The rationale behind this study was the proven efficacy of N-acetylcysteine (NAC; a replenisher of sulfhydryls) and reports on the antioxidant potential of aminoguanidine (AG; an iNOS inhibitor), that might be useful to protect against the toxic implications of AZA. AG (100 mg/kg; i.p.) or NAC (100 mg/kg; i.p.) were administered to the Wistar male rats for 7 days and after that AZA (15 mg/kg, i.p.) was given as a single dose. This caused an increase in the activity of hepatic aminotransferases (AST and ALT) in the serum 24 h after AZA treatment. AZA (7.5 or 15 mg/kg, i.p.) also caused an increase in rat liver lipid peroxides and a lowering of reduced glutathione (GSH) contents. In the other part of experiment, protective effects of AG and NAC were observed on AZA induced hepatotoxicity. NAC significantly protected against the toxic effects produced by AZA. Pretreatment with NAC prevented any change in the activities of both the aminotransferases after AZA. This pretreatment also resulted in a significant decline in the contents of lipid peroxides and a significant elevation in GSH level was evident after AZA treatment. In the group with AG pretreatment the activities of AST and ALT did not increase significantly after AZA when compared to control. However, the lipid peroxides and GSH levels did not have any significant difference when compared to AZA group. These observations also indicate that the improvement in the GSH levels by NAC is the most significant protective mechanism rather than any other mechanistic profile. The protective effect of AG against the enzyme leakage seems to be through the liver cell membrane permeability restoration and is independent of any effects on liver GSH contents.     

Machine learning reveals sequence-function relationships in family 7 glycoside hydrolases

Family 7 glycoside hydrolases (GH7) are among the principal enzymes for cellulose degradation in nature and industrially. These enzymes are often bimodular, including a catalytic domain and carbohydrate-binding module (CBM) attached via a flexible linker, and exhibit an active site that binds cello-oligomers of up to ten glucosyl moieties. GH7 cellulases consist of two major subtypes: cellobiohydrolases (CBH) and endoglucanases (EG). Despite the critical importance of GH7 enzymes, there remain gaps in our understanding of how GH7 sequence and structure relate to function. Here, we employed machine learning to gain data-driven insights into relationships between sequence, structure, and function across the GH7 family. Machine-learning models, trained only on the number of residues in the active-site loops as features, were able to discriminate GH7 CBHs and EGs with up to 99% accuracy, demonstrating that the lengths of loops A4, B2, B3, and B4 strongly correlate with functional subtype across the GH7 family. Classification rules were derived such that specific residues at 42 different sequence positions each predicted the functional subtype with accuracies surpassing 87%. A random forest model trained on residues at 19 positions in the catalytic domain predicted the presence of a CBM with 89.5% accuracy. Our machine learning results recapitulate, as top-performing features, a substantial number of the sequence positions determined by previous experimental studies to play vital roles in GH7 activity. We surmise that the yet-to-be-explored sequence positions among the top-performing features also contribute to GH7 functional variation and may be exploited to understand and manipulate function.     

Effects of sun-drying and exogenous enzymes on nutrients intake,digestibility and nitrogen utilization in sheep fed Atriplex halimus foliages

This study was conducted to assess effects of sun-drying and/or addition of an exogenous enzyme (ENZ) preparation on intake, digestibility of nutrients and recovery values of secondary metabolites (SM) in the gastrointestinal tract of sheep fed Atriplex halimus (AH) foliages. A randomized block design for 28 d was used for four experimental treatments based on either fresh (AH-F) or sun-dried (AH-S) A. halimus foliages in the absence (?ENZ) or presence (+ENZ) of 10 g/sheep/d of the exogenous of ZADO^® enzyme preparation. Three adult sheep weighing 51 ± 2.7 kg were fed for each experimental treatment. The ENZ was added daily with a small amount of concentrate to help balance the dietary metabolizable energy concentration. Nutrient intake and digestibility, N balance and recovery of SM (i.e., total phenolics (TP), saponins (SP), alkaloids (AK), aqueous fraction (AF)) in the gastrointestinal tract were determined. Levels of most nutrients did not differ between AH-F and AH-S foliages, but the AH-S contained less than half of the SM in AH-F. Drying of A. halimus and ENZ addition increased (P=0.001) intake as well as OM and NDFom digestibility (P=0.02). Feed intake and digestibility were higher (P=0.01) in AH-S with ENZ addition. Intake of N by sheep fed the treatment diets depended on DM intake as the dietary concentration of N in the diets was similar. Thus AH-S sheep supplemented with ENZ had higher (P=0.001) N intake. Digestibility of N was similar to DM and OM digestibility, and was higher (P=0.03) in AH-S sheep supplemented with ENZ. Drying and ENZ addition to the diet increased (P=0.004) recovery of all SM. The fate of these compounds in the rumen needs to be evaluated considering that SM have been implicated in fiber and protein degradation in the rumen. The study showed that there are beneficial impacts of sun-drying and/or dietary exogenous enzyme addition for sheep fed A. halimus.     

Protective effect of aminoguanidine against paraquat-induced oxidative stress in the lung of mice

The effect of aminoguanidine (AG) against toxicity of paraquat (PQ), an oxidative-stress inducing substance, in mice was investigated. A single dose of PQ (50 mg/kg, i.p.) induced lung-toxicity, manifested by significant decrease of the activity of angiotensin converting enzyme (ACE) in lung tissue indicating pulmonary capillary endothelial cell damage. Lung toxicity was further evidenced by significant decrease of total sulfhydryl (-SH) content and significant increase in lipid peroxidation measured as malondialdehyde (MDA) in lung tissues. Oral pretreatment of mice with AG (50 mg/kg) in drinking water, starting 5 days before PQ injection and continuing during the experimental period, ameliorated the lung toxicity induced by PQ. This was evidenced by a significant increase in the levels of ACE activity, a significant decrease in lung MDA content and a significant increase in the total sulfhydryl content 24 h after PQ administration. Moreover, pretreatment of mice with AG leads to an increase of the LD(50) value of paraquat. These results indicate that AG is an efficient cytoprotective agent against PQ-induced lung toxicity.