Biofouling effects on the performance of microbial fuel cells and recent advances in biotechnological and chemical strategies for mitigation

The occurrence of biofouling in MFC can cause severe problems such as hindering proton transfer and increasing the ohmic and charge transfer resistance of cathodes, which results in a rapid decline in performance of MFC. This is one of the main reasons why scaling-up of MFCs has not yet been successfully accomplished. The present review article is a wide-ranging attempt to provide insights to the biofouling mechanisms on surfaces of MFC, mainly on proton exchange membranes and cathodes, and their effects on performance of MFC based on theoretical and practical evidence. Various biofouling mitigation techniques for membranes are discussed, including preparation of antifouling composite membranes, modification of the physical and chemical properties of existing membranes, and coating with antifouling agents. For cathodes of MFC, use of Ag nanoparticles, Ag-based composite nanoparticles, and antifouling chemicals is outlined in considerable detail. Finally, prospective techniques for mitigation of biofouling are discussed, which have not been given much previous attention in the field of MFC research. This article will help to enhance understanding of the severity of biofouling issues in MFCs and provides up-to-date solutions. It will be beneficial for scientific communities for further strengthening MFC research and will also help in progressing this cutting-edge technology to scale-up, using the most efficient methods as described here.     

Dynamic antibody specificities and virion concentrations in circulating immune complexes in acute to chronic HIV-1 infection

Understanding the interactions between human immunodeficiency virus type 1 (HIV-1) virions and antibodies (Ab) produced during acute HIV-1 infection (AHI) is critical for defining antibody antiviral capabilities. Antibodies that bind virions may prevent transmission by neutralization of virus or mechanically prevent HIV-1 migration through mucosal layers. In this study, we quantified circulating HIV-1 virion-immune complexes (ICs), present in approximately 90% of AHI subjects, and compared the levels and antibody specificity to those in chronic infection. Circulating HIV-1 virions coated with IgG (immune complexes) were in significantly lower levels relative to the viral load in acute infection than in chronic HIV-1 infection. The specificities of the antibodies in the immune complexes differed between acute and chronic infection (anti-gp41 Ab in acute infection and anti-gp120 in chronic infection), potentially suggesting different roles in immunopathogenesis for complexes arising at different stages of infection. We also determined the ability of circulating IgG from AHI to bind infectious versus noninfectious virions. Similar to a nonneutralizing anti-gp41 monoclonal antibody (MAb), purified plasma IgG from acute HIV-1 subjects bound both infectious and noninfectious virions. This was in contrast to the neutralizing antibody 2G12 MAb that bound predominantly infectious virions. Moreover, the initial antibody response captured acute HIV-1 virions without selection for different HIV-1 envelope sequences. In total, this study demonstrates that the composition of immune complexes are dynamic over the course of HIV-1 infection and are comprised initially of antibodies that nonselectively opsonize both infectious and noninfectious virions, likely contributing to the lack of efficacy of the antibody response during acute infection.     

Genotoxicity and immunogenicity of DNA-advanced glycation end products formed by methylglyoxal and lysine in presence of Cu

The highly reactive electrophile, methylglyoxal (MG), a break down product of carbohydrates, is a major environmental mutagen having potential genotoxic effects. Previous studies have suggested the reaction of MG with free amino groups of proteins forming advanced glycation end products (AGEs). This results in the generation of free radicals which play an important role in pathophysiology of aging and diabetic complications. MG also reacts with free amino group of nucleic acids resulting in the formation of DNA–AGEs. While the formation of nucleoside AGEs has been demonstrated previously, no extensive studies have been performed to assess the genotoxicity and immunogenicity of DNA–AGEs. In this study we report both the genotoxicity and immunogenicity of AGEs formed by MG–Lys–Cu²⁺ system. Genotoxicity of the experimentally generated AGEs was confirmed by comet-assay. Spectroscopical analysis and melting temperature studies suggest structural perturbations in the DNA as a result of modification. This might be due to generation of single-stranded regions and destabilization of hydrogen bonds. Immunogenicity of native and MG–Lys–Cu²⁺-DNA was probed in female rabbits. The modified DNA was highly immunogenic eliciting high titre immunogen specific antibodies, while the unmodified form was almost non-immunogenic. The results show structural perturbations in MG–Lys–Cu²⁺-DNA generating new epitopes that render the molecule immunogenic.     

Arabidopsis CUP-SHAPED COTYLEDON3 regulates postembryonic shoot meristem and organ boundary formation

Overall shoot architecture in higher plants is highly dependent on the activity of embryonic and axillary shoot meristems, which are produced from the basal adaxial boundaries of cotyledons and leaves, respectively. In Arabidopsis thaliana, redundant functions of the CUP-SHAPED COTYLEDON genes CUC1, CUC2, and CUC3 regulate embryonic shoot meristem formation and cotyledon boundary specification. Their functional importance and relationship in postembryonic development, however, is poorly understood. Here, we performed extensive analyses of the embryonic and postembryonic functions of the three CUC genes using multiple combinations of newly isolated mutant alleles. We found significant roles of CUC2 and CUC3, but not CUC1, in axillary meristem formation and boundary specification of various postembryonic shoot organs, such as leaves, stems, and pedicels. In embryogenesis, all three genes make significant contributions, although CUC3 appears to possess, at least partially, a distinct function from that of CUC1 and CUC2. The function of CUC3 and CUC2 overlaps that of LATERAL SUPPRESSOR, which was previously shown to be required for axillary meristem formation. Our results reveal that redundant but partially distinct functions of CUC1, CUC2, and CUC3 are responsible for shoot organ boundary and meristem formation throughout the life cycle in Arabidopsis.     

Improvement of Early Maturing and Climate Resilient Chickpea (<i>Cicer arietinum</i> L.) Cultivars Suitable for Multiple Environments in Bangladesh

Ensuring food security for the rapidly increasing population and changing climatic scenarios are requisites for exploiting the genetic divergence of food crops. A study was undertaken to sort out an early maturing chickpea variety for fitting easily between rice-rice cropping systems in the Eastern Indo-Gangetic Plain of Bangladesh. The trial was comprised of eight elite lines of chickpea and executed at various localities in Bangladesh from 2014– 15 to 2017–18. The result explored the chickpea genotype, BARI Chola-11 remained superior to the rest of the elite genotypes for having a short maturity period (100–106 days), and lesser days to 50% flowering (47– 55 days). The same genotype was recorded to have robust vegetative and reproductive yield attributes including plant height (49–57 cm), podsplant⁻¹ (37–50), and optimum 100 seed weight (19.5–20.6 g). Owing to better yield attributes, BARI Chola-11 resulted in the maximum seed yield (1200–1500 kg ha⁻¹ ) of chickpea and might be recommended for general adoption in the region for boosting nutritional security status through improved productivity under changing climate.     

Biological and computational studies provide insights into Caesalphinia digyna Rottler stems

Caesalpinia digyna (Rottl.) (Family: Fabaceae) is an essential medicinal plant for it's conventional uses against a kind of human disorders. This research aims to investigate the antidiarrheal, antibacterial and antifungal properties of the methanol extract of the stems extracts of the C. digyna (MECD). The in vivo antidiarrheal activity of the stem extracts were evaluated by using castor oil-induced diarrhea, castor oil-induced enteropooling and charcoal induced intestinal transit in mice model. Besides, in vitro antimicrobial potentiality of MECD was investigated by the disc diffusion method. In silico activity of the isolated compounds were performed by Schrödinger-Maestro (Version 11.1) software. In addition, The ADME/T analysis and PASS prediction were implemented by using pass online tools. In the antidiarrheal investigation, the MECD exhibited a notable inhibition rate in all test approaches which were statistically significant (p < 0.05, p < 0.1, p < 0.01). MECD 400 mg/kg showed the maximum antidiarrheal potency in all the test methods. In vitro antimicrobial analysis unveiled that, MECD revealed higher potentiality against almost all pathogens and indicates dose-dependent activity against almost all the bacteria and fungi. In the case of in silico evaluation of anti-diarrheal, anti-bacterial and anti-fungal activity, all three isolated compounds met the pre-conditions of Lipinski's five rules for drug discovery. Pass predicted study also employed for all compounds. However, The chemical constituents of the C. digyna can be a potent source of anti-diarrheal, anti-bacterial and anti-fungal medicine and further modification and simulation studies are required to establish the effectiveness of bioactive compounds.     

Genetic Diversity and Distribution of the Ciguatera-Causing Dinoflagellate Gambierdiscus spp. (Dinophyceae) in Coastal Areas of Japan

Background

The marine epiphytic dinoflagellate genus Gambierdiscus produce toxins that cause ciguatera fish poisoning (CFP): one of the most significant seafood-borne illnesses associated with fish consumption worldwide. So far, occurrences of CFP incidents in Japan have been mainly reported in subtropical areas. A previous phylogeographic study of Japanese Gambierdiscus revealed the existence of two distinct phylotypes: Gambierdiscus sp. type 1 from subtropical and Gambierdiscus sp. type 2 from temperate areas. However, details of the genetic diversity and distribution for Japanese Gambierdiscus are still unclear, because a comprehensive investigation has not been conducted yet.

Methods/Principal Finding

A total of 248 strains were examined from samples mainly collected from western and southern coastal areas of Japan during 2006–2011. The SSU rDNA, the LSU rDNA D8–D10 and the ITS region were selected as genetic markers and phylogenetic analyses were conducted. The genetic diversity of Japanese Gambierdiscus was high since five species/phylotypes were detected: including two reported phylotypes (Gambierdiscus sp. type 1 and Gambierdiscus sp. type 2), two species of Gambierdiscus (G. australes and G. cf. yasumotoi) and a hitherto unreported phylotype Gambierdiscus sp. type 3. The distributions of type 3 and G. cf. yasumotoi were restricted to the temperate and the subtropical area, respectively. On the other hand, type 1, type 2 and G. australes occurred from the subtropical to the temperate area, with a tendency that type 1 and G. australes were dominant in the subtropical area, whereas type 2 was dominant in the temperate area. By using mouse bioassay, type 1, type 3 and G. australes exhibited mouse toxicities.

Conclusions/Significance

This study revealed a surprising diversity of Japanese Gambierdiscus and the distribution of five species/phylotypes displayed clear geographical patterns in Japanese coastal areas. The SSU rDNA and the LSU rDNA D8–D10 as genetic markers are recommended for further use.     

Interactions of Ralstonia solanacearum and Pectobacterium carotovorum with Meloidogyne incognita on potato

Effect of interactions of Meloidogyne incognita with Ralstonia solanacearum and interaction of M. incognita with Pectobacterium carotovorum were studied in sequential and simultaneous inoculations on potato (Solanum tuberosum). Inoculation of M. incognita caused a lesser reduction in plant growth than caused by R. solanacearum. Inoculation of M. incognita plus R. solanacearum caused a greater reduction in plant growth than the damage caused by either pathogen. Inoculation of M. incognita prior to R. solanacearum resulted in a greater reduction in plant growth than R. solanacearum was inoculated prior to M. incognita. However, inoculation of M. incognita or P. carotovorum caused similar reduction in plant growth. Inoculation of P. carotovorum prior to M. incognita caused lesser reduction in plant growth than simultaneous inoculation of both pathogens. Inoculation of M. incognita caused galling in potato roots but the size of galls was small. Inoculation of P. carotovorum or R. solanacearum with M. incognita had adverse effect on galling and nematode multiplication. Wilting or soft rot index was 3 when R. solanacearum or P. carotovorum was inoculated alone. In other treatments, where R. solanacearum or P. carotovorum was inoculated with M. incognita, wilting or soft rot indices were 5.     

Human Parechovirus Genotypes -10, -13 and -15 in Pakistani Children with Acute Dehydrating Gastroenteritis

Human parechoviruses are known to cause asymptomatic to severe clinical illness predominantly respiratory and gastroenetric infections. Despite their global prevalence, epidemiological studies have not been performed in Pakistan. In this study, we retrospectively analyzed 110 fecal specimen and found 26 (24%) positive for viral RNA with HPeV-10 (n = 3, 23%), HPeV-13 (n = 4, 31%) and HPeV-15 (n = 6, 46%) genotypes. Clinical features of patients with different HPeV genotypes were compared. All HPeV positive children were aged ≤4 years (mean 13.92 months). The male-to-female ratio was 1: 1.17 (46.2 vs 53.8%) with significant association (p = .031) to HPeV infectivity. HPeV-10 and -13 were found during summer while HPeV-15 was only detected during late winter season. Disease symptoms were more severe in children infected with HPeV-10 and -13 as compared to HPeV-15. Fever and vomiting were observed in 100% cases of HPeV-10 and -13 while only 17% patients of HPeV-15 had these complaints. Phylogenetic analyses showed that HPeV-10, -13 and -15 strains found in this study have 9–13%, 16.8% and 21.8% nucleotide divergence respectively from the prototype strains and were clustered to distinct genetic lineages. This is the first report of HPeV-15 infection in humans although first identified in rhesus macaques. The arginine-glycine-aspartic acid (RGD) motif present at the C-terminal of VP1 responsible for the viral attachment to cellular integrins was not found in all of these strains. In conclusion, these findings enhance our knowledge related to the epidemiology and genetic diversity of the HPeV in Pakistan and support the need for continued laboratory based surveillance programs especially in infants and neonatal clinical settings. Further, the parechovirus pathogenesis, cross-species transmission and disease reservoirs must be ascertained to adopt better prevention measures.