Rhizobacterial mediated antimetabolites and their significant effect on human pathogens

Background: The emergence of antibiotic resistant bacteria is increasing globally. Therefore, new strategies and exploration of new metabolites are need of the day to combat various diseases.  The aim of the current study is to isolate the rhizobacterial strains from medicinal plants to examine their antibacterial activity against human pathogens.Methods: The total 239 rhizobacterial isolates were screened with agar plug and well diffusion methods, characterized biochemically and identified by Bergey’s manual scheme. In chemical screening, metabolic extracts of rhizobacterial isolates were separated in thin layer chromatography (TLC) and further identified by HPLC. The ability of rhizobacterial strains for optimum metabolite production was checked in vitro under different environmental conditions.Results: Results showed that 31% isolates had antibacterial activity against Bacillus cereus, Bacillus subtilis, E. coccus, E. coli, Salmonella, Klebsiella, Staphylococcus aureus ATCC20737, Staphylococcus aureus ATCC25923 and Neisseria. Gonorrhea ATCC19424, methicillin resistant Staphylococcus aureus 1, methicillin resistant Staphylococcus aureus 6 and methicillin resistant Staphylococcus aureus 8.  Maximum rhizobacterial strains showed best antibacterial activity at 35ᵒC and at pH7. ST5 strain showed significant results against E. coli ETCC and methicillin resistant Staphylococcus aureus-7 (25mm zone of inhibition). The bands of ST5 and ST2 extracts on a TLC plate were detected at Rf value 4.7 and 4.8 respectively. In HPLC, different peaks at different retention times with maximum peak at 2.90 and 2.92 indicating the production of antimetabolites.Conclusion: These rhizobacterial isolates are valuable inputs in natural consortium to produce specific antibacterial metabolites. Demonstrating the structure and purification of these bioactive compounds may enhance the antimicrobial activities which further can be helpful in development of antibiotics.Keywords: Antibiotics; Rhizobacteria; Antimicrobial agents; MRSA; HPL

New host record for parasitic copepod, Lamproglena chinensis Yü, 1937 from marine fish Pampus argenteus

A copepod parasite, Lamproglena chinensis Yü, 1937 was recorded first time from its new marine host Pampus argenteus captured from the coastal waters of Pakistan. This is the first report on the occurrence of Lamproglena chinensis in marine fish in the World. Lamproglena chinensis was reported to parasitize only freshwater fishes in many countries of the world. This species was reported previously to parasitize freshwater fish from Pakistan. The present paper provides the description of Lamproglena chinensis collected from the gill filaments of Pampus argenteus

Population assessment, threats and conservation measures of marsh crocodile at Dasht River, Gwadar

Dasht River is the largest seasonal river in District Gwadar and Turbat which is fed by Nehang and Kech Rivers. The river and its tributariesare good habitat of Marsh crocodile (Crocodylus palustris). Population census of the species revealed that there is a sharp decline in their numbers and are some serious threat to crocodile at Dasht like predation of their eggs by feral dogs, shooting by local people, habitat destruction like construction of dams and agricultural activities, illegal smugglings of crocodile juveniles and frequent tropical cyclones/high floods in the area. There was an alarming decline in the populations during a period of 10 years. There were 99 crocs of the species in 2007-8 having 63 adults, 18 sub adults and 18 juveniles which reduced to only 25 crocs having 23 adults and only 2 juveniles in 2017-18. The decline of adult population and absence of offsprings indicates that the reproduction is not taking place, which is a highly unhealthy and dangerous situation. The habitat degradation needs to be controlled. The current conservation program like might the species which is classified as endangered must be considered for a status of critically endangered species

Status and diversity of coastal avian fauna in Gwadar peninsula, Balochistan

The 1050 km long coastline of Pakistan, extends from Sir Creek in the southeast of Indus delta to Gwadar Bay in the west. This article is based on diversity, habitat, status and distribution of different species of coastal birds present in the Gwadar coast. Observation of birds was done during winter season at four different sites. The habitat is important for different coastal birds like terns, gulls, pelicans and waders including resident and migratory species. A total of 55 species were recorded from the entire area. The species richness was higher at two sites. The birds were seen in higher numbers at uninhabited points compared to those near the populated area or the port. Shannon diversity index for bird community was calculated for four sites namely Shabi Estuary, Gwadar East Bay, Gwadar West Bay and Gurab, where the diversity was found to be 2.82, 2.27, 2.33 and 2.40 respectively. Birds of Common Sandpiper (Actitishy poleucos), Common Teal (Anas crecca), Wigeon (Anas Penelope), Shoveller (Anas clypeata), Pochard (Aythya ferina), Common Coot (Fulica atra), Grey Plover (Pluvialis squatarola), Kentish Plover (Charadrius alexandriunus), Dusk Red Shank (Tringa erythropus) and Great White Pelicans (Pelecanus onocrotalus) have been recorded in large numbers during the study period. Some vulnerable species for e.g. Pochard (Aythya ferina) and endangered species for e.g. Great Knot (Calidris tenuirostris), Egyptian Vulture (Neophron percnopterus), and two near threatened species Oyster catcher (Haematus ostralegus) and Dalmation Pelican (Pelecanus crispus) were also recorded. The major threats to the ecosystem are habitat degradation due to port construction, urbanization, hunting, poaching and other anthropogenic activities

Biodeterioration of Microplastics: A Promising Step towards Plastics Waste Management

Polyethylene and Polyester materials are resistant to degradation and a significant source of microplastics pollution, which is an emerging concern. In the present study, the potential of a dumped site bacterial community was evaluated. After primary screening, it was observed that 68.5% were linear low-density polyethylene, 33.3% were high-density, and 12.9% were Polyester degraders. Five strains were chosen for secondary screening, in which they were monitored by FTIR, SEM and weight loss degradation trials. Major results were observed for Alcaligenes faecalis (MK517568) and Bacillus cereus (MK517567), as they showed the highest degradation activity. Alcaligenes faecalis (MK517568) degrades LLDPE by 3.5%, HDPE by 5.8% and Polyester by 17.3%. Bacillus cereus (MK517567) is better tolerated at 30 °C and degrades Polyester by 29%. Changes in infrared spectra indicated degradation pathways of different strains depending on the types of plastics targeted. Through SEM analysis, groves, piths and holes were observed on the surface. These findings suggest that soil bacteria develop an effective mechanism for degradation of microplastics and beads that enables them to utilize plastics as a source of energy without the need for pre-treatments, which highlights the importance of these soil bacteria for the future of effective plastic waste management in a soil environment