Pilot-scale production of mosquitocidal toxins by Bacillus thuringiensis and Lysinibacillus sphaericus under solid-state fermentation

Mosquitocidal toxins of Bacillus thuringiensis israelensis (Bti) and Lysinibacillus sphaericus 14N1 (Ls14N1) were produced under solid-state fermentation using agro-industrial wastes. Sugar beet pulp–sesame meal (1:1) and wheat germ meal–linen meal (1:1) at 9% were the efficient substrate mixtures for the growth and toxin production of Bti and Ls14N1, respectively. Bti was more active after the addition of beef extract (0.2%) or yeast extract (0.5%) to the medium. On the other hand, the addition of yeast extract (0.2%) or NYSM salts (2%) significantly enhanced the toxicity produced by Ls14N1. The optimum conditions for the maximum toxicity of Bti were at pH 7–8, 20–30% moisture, 4–10% inoculum and 7 days incubation. For Ls14N1, the best conditions were pH 6.5–7.5, 20–30% moisture, 4–10% inoculum and 5 days incubation. It was found that the best thickness of carrier-substrates in the plate (15?cm in diameter) for the maximum mosquitocidal activity was about 0.5?cm for Bti and 0.5–1?cm for Ls14N1. Pilot-scale production in aluminium trays applying the above conditions showed a decrement of toxicity of fermented cultures and some plates were contaminated. These problems were dissolved by reducing the moisture content to 15%, increasing inoculum to 10% and manual agitation of trays every-day.     

Identification of a series of 1,3,4-oxadiazol-2-amines as potent alpha-7 agonists with efficacy in the novel object recognition model of cognition

A series of α7 nicotinic acetylcholine receptor full-agonists with a 1,3,4-oxadiazol-2-amine core has been discovered. Systematic exploration of the structure-activity relationships for both α7 potency and selectivity with respect to interaction with the hERG channel are described. Further profiling led to the identification of compound 22, a potent full agonist showing efficacy in the novel object recognition model of cognition enhancement.     

Epigenetic modification in 4T1 mouse breast cancer model by artificial light at night and melatonin – the role of DNA-methyltransferase

Currently, one of the most disputed hypotheses regarding breast cancer (BC) development is exposure to short wavelength artificial light at night (ALAN) as multiple studies suggest a possible link between them. This link is suggested to be mediated by nocturnal melatonin suppression that plays an integral role in circadian regulations including cell division. The objective of the research was to evaluate effects of 1 × 30 min/midnight ALAN (134 µ Wcm^?2, 460 nm) with or without nocturnal melatonin supplement on tumor development and epigenetic responses in 4T1 tumor-bearing BALB/c mice. Mice were monitored for body mass (W_b) and tumor volume for 3 weeks and thereafter urine samples were collected at regular intervals for determining daily rhythms of 6-sulfatoxymelatonin (6-SMT). Finally, mice were sacrificed and the tumor, lungs, liver, and spleen were excised for analyzing the total activity of DNA methyltransferases (DNMT) and global DNA methylation (GDM) levels. Mice exposed to ALAN significantly reduced 6-SMT levels and increased W_b, tumor volume, and lung metastasis compared with controls. These effects were diminished by melatonin. The DNMT activity and GDM levels showed tissue-specific response. The enzymatic activity and GDM levels were lower in tumor and liver and higher in spleen and lungs under ALAN compared with controls. Our results suggest that ALAN disrupts the melatonin rhythm and potentially leading to increased BC burden by affecting DNMT activity and GDM levels. These data may also be applicable to early detection and management of BC by monitoring melatonin and GDM levels as early biomarker of ALAN circadian disruption.     

Influence of phenolics on the sensitivity of free and immobilized bioluminescent Acinetobacter bacterium

In this work, the constructed bioluminescent Acinetobacter strain DF4/PUTK2 was employed to assess the toxicity of phenolic compounds and the 5 min EC50 values were calculated. The results of the DF4/PUTK2 assay were further evaluated by comparing with the results of the Vibrio fischeri luminescence inhibition assay. To develop a bioassay system appropriate to be used in continuous toxicity testing, strain DF4/PUTK2 was subjected for immobilization in microtiter plates into the matrices Ca-alginate, polyacrylamide, agar and agarose. After a choice of materials was tried, Ca-alginate was selected as the most suitable candidate material. Because, it could be stored at least 8 weeks at 4 °C, during which the ability of the bioreporter DF4/PUTK2 to detect the toxicity of phenolics was maintained. However, the stability of the bioluminescence for DF4/PUTK2 cells immobilized into agarose and agar was significantly less than that of cells stored in alginate suspensions. This study recommended that luxCDABE-marked Acinetobacter strain DF4/PUTK2 could be employed to assay the ecotoxicity of environmental samples contaminated with phenols. The host strain of the bioreporter DF4/PUTK2 is Acinetobacter strain DF4. It is known that members of the genus Acinetobacter are widespread in nature and also involved in biodegradation, leaching and removal of several organic and inorganic man-made hazardous wastes.     

A comprehensive biochemical characterization of settlement stage leptocephalus larvae of bonefish (Albula vulpes)

Little is known about early development of the near-threatened bonefish (Albula vulpes), a member of superorder Elopomorpha. Members of Elopomorpha are partially defined by their synapomorphic leptocephalus larval stage, for which the nutritional requirements are not well understood. Characterizing the nutritional profile, including major nutrients (such as lipids) used for energetic processes, can help to gain a better understanding of the nutritional requirements for leptocephalus larvae. A total of 24 settlement stage A. vulpes leptocephalus larvae were collected at Long Caye Island, Belize. Samples were used to determine various biochemical characteristics including lipid class, fatty acid and glycosaminoglycan compositions. Each of these biochemical components plays a role in early developmental processes such as cellular membrane formation and is crucial for healthy development. Biochemical characteristics of settlement stage A. vulpes leptocephalus are presented in this study for the first time. The dominant lipid classes and fatty acids detected in these samples were consistent with prior studies using closely related species like the Japanese eel, indicating possible similarities in diets at this stage. In the future, similar analyses can be applied to other species that share the leptocephalus life stage to determine if nutritional requirements at this stage of development are unique to this species. The findings in this study will also help to facilitate the establishment of adequate aquaculture systems for captive bonefish, ultimately leading to improved management strategies for wild bonefish habitats.     

Improvement in infected wound healing in type 1 diabetic rat by the synergistic effect of photobiomodulation therapy and conditioned medium

We investigated the effects of photobiomodulation therapy (PBMT) and conditioned medium (CM) of human bone marrow mesenchymal stem cells (hBM-MSC) individually and/or in combination on the stereological parameters and the expression of basic fibroblast growth factor (bFGF), hypoxia-inducible factor (HIF-1α), and stromal cell–derived factor-1α (SDF-1α) in a wound model infected with methicillin-resistant Staphylococcus aureus (MRSA) in diabetic rats. CM was provided by culturing hBM-MSCs. Type 1 diabetes mellitus (T1DM) was induced in 72 rats, divided into four groups, harboring 18 rats each: group 1 served as a control group, group 2 received PBMT, group 3 received CM, and group 4 received CM + PBMT. On days 4, 7, and 15, six animals from each group were euthanized and the skin samples were separated for stereology examination and gene expression analysis by real-time polymerase chain reaction. In the CM + PBMT, CM, and PBMT groups, significant decreases were induced in the number of neutrophils (1460 ± 93, 1854 ± 138, 1719 ± 248) and macrophages (539 ± 69, 804 ± 63, 912 ± 41), and significant increases in the number of fibroblasts (1073 ± 116, 836 ± 75, 912 ± 41) and angiogenesis (15 230 ± 516, 13 318 ± 1116, 14 041 ± 867), compared with those of the control group (2690 ± 371, 1139 ± 145, 566 ± 90, 12 585 ± 1219). Interestingly, the findings of the stereological examination in the CM + PBMT group were statistically more significant than those in the other groups. In the PBMT group, in most cases, the expression of bFGF, HIF-1α, and SDF-1α, on day 4 (27.7 ± 0.14, 28.8 ± 0.52, 27.5 ± 0.54) and day 7 (26.8 ± 1.4, 29.6 ± 1.4, 28.3 ± 1.2) were more significant than those in the control (day 4, 19.3 ± 0.42, 25.5 ± 0.08, 22.6 ± 0.04; day 7, 22.3 ± 0.22, 28.3 ± 0.59, 24.3 ± 0.19) and other treatment groups. The application of PBMT + CM induced anti-inflammatory and angiogenic activities, and hastened wound healing process in a T1 DM model of MRSA infected wound.     

Is photobleaching necessary for Raman imaging of bone tissue using a green laser?

Raman microspectroscopy is widely used for musculoskeletal tissues studies. But the fluorescence background obscures prominent Raman bands of mineral and matrix components of bone tissue. A 532-nm laser irradiation has been used efficiently to remove the fluorescence background from Raman spectra of cortical bone. Photochemical bleaching reduces over 80% of the fluorescence background after 2 h and is found to be nondestructive within 40 min. The use of electron multiplying couple charge detector (EMCCD) enables to acquire Raman spectra of bone tissues within 1-5 s range and to obtain Raman images less than in 10 min.     

烟粉虱B生物型若虫、皮蜕及成虫提取物对双斑蚜小蜂行为的影响

烟粉虱B生物型的若虫、皮蜕及其成虫的提取物作为一种利它素信息源,在室内对其在双斑蚜小蜂寻找寄主取食、寄生行为的影响进行了生物测定。烟粉虱的若虫、皮蜕及其成虫分别用正己烷、乙醇和无菌水进行粗提。研究结果发现,双斑蚜小蜂在处理区寻找寄主停留的时间高于对照区。在处理区,双斑蚜小蜂行动活泼,对利它素源表现出高的正趋向性和选择性。对于同一利它素源、同一提取介质的两种不同浓度,双斑蚜小蜂在若虫 水提取物的高浓度区停留的时间（111.23s）最长,与在低浓度区的停留时间差异显著;而在烟粉虱皮蜕及其成虫的水、正己烷和乙醇提取物处理区,不同浓度的提取物对蚜小蜂停留的时间影响差异不显著。本研究的结果表明,利它素可以增加蚜小蜂寻找寄主的效率,有利于蚜小蜂寻找到适宜的寄主。