Engineering strategies and applications of cyanobacterial exopolysaccharides: A review on past achievements and recent perspectives

Cyanobacteria are ideally suited for developing sustainable biological products but are underdeveloped due to a lack of genetic tools. Exopolysaccharide (EPS) is one of the essential bioproducts with widespread industrial applications. Despite their unique structural characteristics associated with distinct biological and physicochemical aspects, EPS from cyanobacteria has been underexplored. However, it is expected to accelerate in the near future due to the utilization of low-cost cyanobacterial platforms and readily available information on the structural data and specific features of these biopolymers. In recent years, cyanobacterial EPSs have attracted growing scientific attention due to their simple renewability, rheological characteristics, massive production, and potential uses in several biotechnology domains. This review focuses on the most recent research on potential new EPS producers and their distinct compositions responsible for novel biological activities. Additionally, nutritional and process parameters discovered recently for enhancing EPS production and engineering strategies applied currently to control the biosynthetic pathway for enhanced EPS production are critically highlighted. The process intensification of previously developed EPS extraction and purification processes from cyanobacterial biomass is also extensively explained. Furthermore, the newly reported biotechnological applications of cyanobacterial exopolysaccharides are also discussed.

Astaxanthin from microalgae: A review on structure, biosynthesis, production strategies and application

Astaxanthin is a red-colored secondary metabolite with excellent antioxidant properties, typically finds application as foods, feed, cosmetics, nutraceuticals, and medications. Astaxanthin is usually produced synthetically using chemicals and costs less as compared to the natural astaxanthin obtained from fish, shrimps, and microorganisms. Over the decades, astaxanthin has been naturally synthesized from Haematococcus pluvialis in commercial scales and remains exceptional, attributed to its higher bioactive properties as compared to synthetic astaxanthin. However, the production cost of algal astaxanthin is still high due to several bottlenecks prevailing in the upstream and downstream processes. To that end, the present study intends to review the recent trends and advancements in astaxanthin production from microalgae. The structure of astaxanthin, sources, production strategies of microalgal astaxanthin, and factors influencing the synthesis of microalgal astaxanthin were discussed while detailing the pathway involved in astaxanthin biosynthesis. The study also discusses the relevant downstream process used in commercial scales and details the applications of astaxanthin in various health related issues.

A new species of Hydatothrips (Thysanoptera, Thripidae) from India with one new record

A remarkable new species, Hydatothrips longirostris, with an elongate mouth cone extending to the metasternum is described from India. Dendrothrips glynn Mound, a dendrothripine species, is newly recorded from India.

First report of Neopestalotiopsis clavispora causing cashew leaf blight disease in India

Cashew (Anacardium occidentale) is an important commercial crop and highly prone to many biotic and abiotic stress. During March 2021, severe leaf blight symptoms were observed in Priyanka variety with 25-30% incidence grown under greenhouse nursery at ICAR-Directorate of Cashew Research (ICAR-DCR), Puttur (12º74'08.92"N; 75º22'97.22"E), Karnataka. Initial symptoms include small, irregular necrotic spots and later, the spots enlarged and covered major portion of the leaf lamina. In severe infection, leaves exhibited coalescing of spots leading to blight appearance. The infected leaves were randomly collected (n=5) and surface sterilized with 1% sodium hypochlorite for 1 min followed by three washes in sterile distilled water (SDW). Samples were plated on PDA plates amended with Rifampicin (40 mg/L) and kept for incubation at 25±2 oC for 5 days (12/12 h dark light period). A white-greyish, aerial, cottony mycelium on upper side with light yellow colour on the reverse side was consistently isolated. The black viscous acervuli were observed after 10-12 days of incubation. The conidia were fusiform, five-celled, versicoloured with three olivaceous brown median cells, two terminal hyaline cells, measured 23.3±2.12 - 28.33±2.7 x 3.6±0.8 - 4.28±0.78 µm (n=30). The apical cells had two to three flexuous, unbranched appendages, and basal appendage was solitary, tubular and unbranched. Morphological and cultural characteristics confirmed the pathogen as Neopestalotiopsis sp. (Maharachchikumbura et al. 2012). Further, two representative isolates (CLB_SCN1 & CLB_SCN2) were subjected for molecular characterization selected for molecular identification based on ITS-rDNA, tef-1α and tub2 gene sequences and phylogenetic analysis. Genomic DNA was isolated from 15 days old cultures and internal transcribed spacer (ITS) of ribosomal DNA (rDNA) (White et al. 1990), translation elongation factor 1α (tef-1α) gene (O'Donnell et al. 1998) and beta tubulin (tub2) using ITS1/ITS4, TEF1/TEF2 and Bt2a/Bt2b (Carbone and Kohn 1999; Glass and Donaldson 1995) were amplified using primer pairs respectively. PCR amplicons were sequenced, and the sequences were deposited in GenBank (accession numbers: ITS: OP880881.1, OP880882.1; tef-1α: OP882579.1, OP882580.1; and tub2: OP882581., OP882582.1). The phylogeny was constructed based on combined ITS, tef-1a, and tub2 regions. Neighbour-Joining (NJ) analysis was conducted and the tree was constructed with the substitution models (branch support was evaluated by 1,000 bootstrap replications). Combined phylogeny confirmed that the sequences shared a common clade with N. clavispora. Hence, morphological, microscopic and molecular characterization confirmed the pathogen as N. clavispora. The pathogenicity test was done on six months old healthy grafts of Priyanka variety (n=9) and repeated thrice. Conidial suspension (2×106 spores/ml) of N. clavispora CLB_SCN1 (15 days old culture) was sprayed on the healthy cashew seedlings, and kept in greenhouse by covering with polythene bags for 24 h (>80 % RH) and maintained under greenhouse condition. The control grafts were inoculated with SDW. The inoculated plants showed blight symptoms after 7-10-day post inoculation and control remained heathy. Re-isolation was done from the symptomatic leaves and identity was confirmed using cultural and molecular studies. Earlier reports showed that, N. clavispora has been reported to cause cardamom leaf blight (Biju et al 2018) and leaf spot disease of plum (Banerjee and Rana 2020). To best of our knowledge, this is the first report of cashew leaf blight disease caused by N. clavispora from India (Farr and Rossman, 2022). Early detection will help farmer in better management and avoiding economic loss caused by N. clavispora.

Medical image fusion using fuzzy adaptive reduced pulse coupled neural networks

This paper addresses a novel neuro-fuzzy-based approach to set the weighted linking strength of parameter - adaptive reduced pulse coupled neural networks. In reduced PCNN based medical image fusion algorithms, it is quite essential to evaluate the prominence of each pixel in an image. The fusion performance in turn depends on the linking factor, internal activity. Thus, we need to set these values of reduced PCNN in a more adaptive manner with fewer complications and uncertainties. For this, the weighted linking strength i.e., lambda of the reduced PCNN neurons is attentively set by a fuzzy-based approach. Here, lambda of neurons is represented as fuzzy membership values using the activity level measures such as local information entropy and energy. Finally, a new model called-Fuzzy adaptive reduced pulse coupled neural networks is developed by reducing the number of parameters and fuzzy adaptive settings of them. This leads to a very less complicated network and more computational efficacy, which is a prominent part of health care requirements. The proposed scheme is free from the shortcomings such as loss of boundaries, structural details, unwanted artifacts, degradations, etc. Subjective and objective evaluations show better performance of this new approach compared to the existing techniques.

Multi-modal Medical Image Fusion Algorithm Based on Spatial Frequency Motivated PA-PCNN in the NSST Domain

BACKGROUND

Image fusion has been grown as an effectual method in diseases related diagnosis schemes.

METHODS

In this paper, a new method for combining multimodal medical images using spatial frequency motivated parameter-adaptive PCNN (SF-PAPCNN) is suggested. The multi- modal images are disintegrated into frequency bands by using decomposition NSST. The coefficients of low frequency bands are selected using maximum rule. The coefficients of high frequency bands are combined by SF-PAPCNN.

METHODS

In this paper, a new method for combining multimodal medical images using spatial frequency motivated parameter-adaptive PCNN (SF-PAPCNN) is suggested. The multi-modal images are disintegrated into frequency bands by using decomposition NSST. The coefficients of low frequency bands are selected using maximum rule. The coefficients of high frequency bands are combined by SF-PAPCNN.

RESULTS

The fused medical images is obtained by applying INSST to above coefficients.

CONCLUSION

The quality metrics such as entropy ENT, fusion symmetry FS, deviation STD, mutual information Q_MI and edge strength Q_AB/F are used to validate the efficacy of suggested scheme.

A first report of egg parasitism in the Tropical Tasar Silkworm Antheraea mylitta (Drury) occurring on cashew

The present study has documented egg parasitism in Tropical Tasar Silkworm for the first time. The parasitoid is Anastatus leithi (Walker) belonging to Eupelmidae family.  It is a solitary koinobiont endoparasitoid, emerges out as adults from the tasar eggs in 17-20 days during August- September. The parasitism rate was recorded at 11.90 percentage.

Floating tablets of hydralazine hydrochloride: optimization and evaluation

Hydralazine hydrochloride has a half-life of 2 to 4 hours with an oral bioavailability of 26-50%. Since hydralazine has a demethylating effect on various suppressor genes, it can be used in various types of cancer to support chemotherapy. The purpose of this study was to optimize and evaluate floating tablets of hydralazine hydrochloride designed to prolong the gastric residence time and to provide controlled release of the drug for 14 h. The floating tablets of hydralazine hydrochloride were prepared by the wet granulation method. Semi-synthetic polymers of hydroxy propyl methyl cellulose (HPMC K100M) and ethyl cellulose were used as the release retarding agents. A 2² factorial design was applied to systematically optimize the drug release profile. The concentrations of HPMC K100M and ethyl cellulose were optimized to provide controlled release of hydralazine for 14h. Non-Fickian diffusion release transport was confirmed as the release mechanism for the optimized formulation and the predicted values agreed well with the experimental values. Drug excipient compatibility studies were investigated by FTIR, DSC and XRD. These data indicate that there were no chemical interactions between the drug and the polymer. In vivo X-ray imaging showed floating tablet performance in rabbits.

Nm23 expression in retinoblastoma

PURPOSE

Nm23 is a metastasis-suppressor protein. Decreased nm23 protein contributes to aggressiveness in many tumors. Nm23 immunoreactivity was studied in retinoblastoma and correlated with differentiation and invasiveness.

METHODS

Immunohistochemistry was performed on 73 formalin-fixed, paraffin-embedded specimens of retinoblastoma. Western blot was conducted to confirm the immunohistochemical study. Prognostic features such as differentiation, invasion of choroid, optic nerve, and orbit, and metastasis were analyzed.

RESULTS

Intense nm23 immunoreactivity was seen in 61% of the retinoblastomas with no invasion and faint nm23 immunoreactivity was seen in 85% of the retinoblastomas with invasion (p < 0.001). Poorly differentiated retinoblastoma showed decreased nm23 immunoreactivity compared to well-differentiated retinoblastomas (p = 0.02). An inverse correlation was observed between invasion of choroid, optic nerve, orbit, and metastasis, and nm23 immunoreactivity. Western blot assays of fresh tumor extracts confirmed the immunohistochemical findings.

CONCLUSIONS

Decreased nm23 immunoreactivity was seen in poorly differentiated retinoblastomas and in retinoblastomas with invasiveness. These findings may lay the groundwork for further studies to better understand the molecular mechanisms and provide a more accurate prediction of invasion and metastasis of retinoblastoma.

Resistance of Mycobacterium tuberculosis to the first line anti tubercular drugs--a twenty year review

Tuberculosis and more so the multi drug resistant variety has been thrust into the forefront as a serious and life threatening illness in recent years. The advent of AIDS contributes to this substantially, especially in the developed world where it had become practically non- existent. We reviewed our data over the past 20 years with a view to determine when drug resistance began to manifest in the strains.

Gross photography of ophthalmic pathology specimens

Removal of the entire eyeball or a portion of it is required in many ophthalmic conditions. The gross features of such specimens provide valuable information. Gross photography of an intraocular tumour, ruptured eyeball or other pathological specimens including lid lesions, orbital tumors, intraocular lens implants, intraocular and extraocular parasites, retinal pathology such as haemorrhages and peripheral degenerations, establishes a permanent documentation. We herein describe the technique of gross photography of such valuable specimens, using a dissecting microscope with a special arrangement. This technique is currently used by us with gratifying results.