Fructophilic lactic acid bacteria (FLAB) are heterofermentative and related to the genera Fructilactobacillus, Convivina, Leuconostoc, Oenococcus and Weissella. Although they generally prefer fructose above glucose, obligate heterofermentative species will ferment glucose in the presence of external electron acceptors such as pyruvate and fructose. Little is known about the presence of FLAB in the human gut, let alone probiotic properties. In this review we discuss the possible role FLAB may have in the human gastro-intestinal tract (GIT) and highlight the advantages and disadvantages these bacteria may have in individuals with a diet high in fructose.
Collecting environmental information of farmland is very important to the development of modern agricultural techniques. Precision farming and modern agricultural production require timely and accurate environmental information. The main task of this study was to develop a field-based Pocket Personal Computer (PC) data acquisition and processing terminal and a wireless sensor network (WSN) monitoring module, which are used to manage the working status of the field wireless sensor and to collect and record the output of the wireless sensor automatically. The ZigBee module was mainly used for wireless communication between Personal Digital Assistant (PDA) and mobile sensor nodes. The GPS module was used to obtain position information. The General Packet Radio Service (GPRS) module was used to upload the binding information of the node number, position information and agricultural information through the TCP/IP to the remote PC. The test of the whole system indicated that the system can work outside in the field. The experiment of the link quality indication (LQI) at different heights indicated that the signal would be better if the height of the ZigBee antenna was higher than 60 cm, meanwhile the LQI values would be greater than 40 at different distances. It showed that 60 cm was the least height for a better link quality.
This study determined the optimal nursery diet for neonatal black soldier fly (BSF) (Hermetia illucens) larvae. The standard specifications of a poultry layer hen (feed source often used for larvae rearing) was used for the formulation of the control diet (L120), whilst an iso-nitrogenous and iso-energetic diet was formulated that included animal protein (10% spray dried blood meal; L120B). Also, the carcass milling technique was used to determine the ideal amino acid profile of the animals. Two diets were subsequently formulated according to this profile i.e. a plant protein based diet (IAAP) and a diet containing 10% spray dried blood meal (IAAPB). Thirdly, the addition of sterols to the diets were tested with the addition of sterols in the form of pork brains (3%) to both the L120 and IAAP diets. Lastly, a commercial store bought layer mash was used as a second control diet. These seven treatments were replicated eight times in 100 ml pill pots, each pot being inoculated with 100 neonates. Results obtained showed that the inclusion of animal protein in the diet significantly increased survivability by 25% from 69.8±3.98 to 91.3±4.26% in layer mash diets which was similar to that of the other blood meal diets (92.0±3.98 and 93.9±3.98%, respectively). The treatments that included a sterol source yielded the lowest number of larvae. The change in physical characteristics of these diets probably resulted in the low yield rather than the sterols per se and further research in this regard is recommended. In this study cheaper, more efficient feeds were developed for feeding BSF neonates using the ideal amino acid profile of the animals which resulted in the establishing of an initial matrix for the nutrient requirements of these animals.
Edible insects have recently been considered as a potential food source that may solve problems of malnutrition and starvation worldwide. However, studies exploring insects as food sources are mainly focused on entomophagy and nutrition rather than the potential risks of excessive metabolite contents, such as purine and uric acid. In this study, we analysed guanine, hypoxanthine, xanthine, adenine and uric acid concentrations in 11 species of edible insects from Yunnan and Guizhou provinces in Southwest China, including 5 species of dragonfly, 3 species of wasp and a single species of locust, mealworm and silkworm. Purine and uric acid contents differed distinctly between these insects, and guanine and xanthine were the dominant purines in all samples. The proportions of 4 purines in the total purine content of these insects differed markedly from those in meat samples from poultry and livestock, and uric acid contents varied significantly between aquatic insects and terricolous insects, such as silkworm pupa. Taken together, the present data show that most edible insects are potent food sources of purine.
The microbiome of the human gastrointestinal tract (GIT) consists of billions of bacteria, fungi and viruses, of which bacteria play the most important role in nutrition, immune development, production of vitamins and maintaining a well-balanced (homeostatic) microbial population. Many papers have been published on the microbiota in the human GIT, but little is known about the first group of bacteria that colonises an infant. The intestinal tract of an unborn is, despite general belief, not sterile, but contains bacteria that have been transferred from the mother. This opens a new research field and may change our understanding about the role bacteria play in early life, the selection of strains with probiotic properties and the treatment of diseases related to bacterial infections. Differences in bacterial populations isolated from meconia may provide answers to the prevention of certain forms of diabetes. More research is now focusing on the effect that a genetically diverse group, versus a much simpler microbial population, may have on the development of a homeostatic gut microbiome. The effect different bacterial species have on the gut-associated lymphoid tissue and cascade of immune responses has been well researched, but we still fail in identifying the ideal group of intestinal bacteria and if we do, it will certainly not be possible to maintain homeostasis with so many challenges the gut faces. Changes in diet, antibiotics, food preservatives and stress are some of the factors we would like to control, but more than often fail to do so. The physiology and genetics of the GIT changes with age and so the microbiome. This review summarises factors involved in the regulation of a gut microbiome.
Probiotics play an important role in maintaining a healthy and stable intestinal microbiota, primarily by preventing infection. Probiotic lactic acid bacteria (LAB) are known to be inhibitory to many bacterial enteric pathogens, including antibiotic-resistant strains. Whilst the positive role that probiotics have on human physiology, specifically in the treatment or prevention of specific infectious diseases of the gastro-intestinal tract (GIT) is known, the precise mechanistic basis of these effects remains a major research goal. In this study, molecular evidence to underpin the protective and anti-listerial effect of Lactobacillus plantarum 423 and Enterococcus mundtii ST4SA against orally administered Listeria monocytogenes EGDe in the GIT of mice is provided. Bacteriocins plantaricin 423 and mundticin ST4SA, produced by L. plantarum 423 and E. mundtii ST4SA, respectively, inhibited the growth of L. monocytogenes in vitro and in vivo. Bacteriocin-negative mutants of L. plantarum 423 and E. mundtii ST4SA failed to exclude L. monocytogenes EGDe from the gastrointestinal tract (GIT) of mice. Furthermore, L. plantarum 423 and E. mundtii ST4SA failed to inhibit recombinant strains of L. monocytogenes EGDe in vivo that expressed the immunity proteins of the two bacteriocins. These results confirmed that bacteriocins plantaricin 423 and mundticin ST4SA acted as anti-infective mediators in vivo. Compared to wild type strains, mutants of L. plantarum 423 and E. mundtii ST4SA, in which the adhesion genes were knocked out, were less effective in the exclusion of L. monocytogenes EGDe from the GIT of mice. This work demonstrates the importance of bacteriocin and adhesion genes as probiotic anti-infective mechanisms.
The study reports on a simple gravimetrical analysis to determine the chitin content of insect larvae. Hermetia illucens larvae, 16 days of age, was used as sample material. The method of analysis comprised of a defatting treatment by means of rapid solvent extraction (2:1 chloroform : methanol), followed by a treatment with 1 M HCL (demineralisation) and 1 M NaOH (deproteinisation). The nitrogen content of the obtained chitin was determined and compared to that of the nitrogen content of pure chitin (6.89). The chitin content of H. illucens larvae was determined to be 5.68±0.15% with a nitrogen content of 6.43±0.038 (mean ± standard error). The average nitrogen content of the isolated chitin was lower than the theoretical value calculated for pure chitin. This indicated that there was still a small amount of inorganic compounds present in the chitin of the insect larvae after applying the developed analytical procedures. This was confirmed by the ash value of the isolated chitin (1.50±0.06%) (mean ± standard error). The analysis is simple and accurate, which gives repeatable results, for the determination of the chitin content of H. illucens larvae. Further studies regarding the demineralisation treatment could improve the accuracy of the method due to the removal of all inorganic components. Future studies could also investigate the accuracy of the protocol on other insect species.
The bacterial strain SF857 was isolated from the entomopathogenic nematode, Steinernema bakwenae SF857, found in soil samples of St Lucie cherry, a species of cherry tree, from the Muriti farm, close to Kroondal (25°44′E, 59°99′S) in the northwest province of South Africa. Strain SF857 is Gram-negative, catalase and oxidase-negative, and lecithinase-positive. Strain SF857 shared the highest 16S rRNA gene sequence similarity (97.7%) with the type strain of Xenorhabdus ishibashii. However, a comparison of housekeeping gene sequences showed that strain SF857 grouped closer to X. griffiniae, X. ehlersii and X. thuongxuanensis than to X. ishibashii. Digital DNA-DNA hybridisation (dDDH) between strain SF857 and all Xenorhabdus spp. is less than the 70% species threshold, confirming that the strain belongs to a separate species. Furthermore, the biochemical characteristics of strain SF857 differ from other Xenorhabdus spp. Based on these findings, strain SF857 represents a novel species within the genus Xenorhabdus, for which the name Xenorhabdus bakwenae sp. n. (type strain SF857T) is proposed. Pathogenicity bioassays with last-instar Cydia pomonella showed S. bakwenae to be highly virulent, with potential use as a biocontrol agent in apple orchards.