Genes of unknown function constitute a considerable fraction of most bacterial genomes. In a Tn5-based search for stress response genes in the nitrogen-fixing facultative endosymbiont Sinorhizobium (Ensifer) meliloti, we identified a previously uncharacterized gene required for growth on solid media with increased NaCl concentrations. The encoded protein carries a predicted thioredoxin fold and deletion of the gene also results in increased sensitivity to hydrogen peroxide and cumene hydroperoxide. We have designated the gene srlA (stress resistance locus A) based on these phenotypes. A deletion mutant yields phenotypic revertants on high salt medium and genome sequencing revealed that all revertants carry a mutation in genes homologous to either cenK or cenR. srlA promoter activity is abolished in these revertant host backgrounds and in a strain carrying a deletion in cenK. We also observed that the srlA promoter is autoregulated, displaying low activity in a wildtype (wt) host background and high activity in the srl deletion mutant background. The srlA promoter includes a conserved inverted repeat directly upstream of the predicted −35 subsequence. A mutational analysis demonstrated that the site is required for the high promoter activity in the srlA deletion background. Electromobility shift assays using purified wildtype CenR response regulator and a D55E phosphomimetic derivative suggest this protein acts as a likely Class II activator by binding promoter DNA. These results document the first identified CenK–CenR regulon member in S. meliloti and demonstrate this two-component regulatory system and gene srlA influences cellular growth and persistence under certain stress-inducing conditions.

This study was conducted to evaluate and compare the water quality of Buhisan, Bulacao and Lahug rivers in Cebu, Philippines using coliforms as indicators. Monthly sampling started from November 2011 to April 2012 in the upstream, midstream and downstream stations. The multiple tube fermentation technique was used for the analysis of coliforms. High total and fecal coliform counts were observed in the three rivers from February to April, but the difference in values across time was not significant. Fecal coliform counts of Buhisan and Bulacao rivers differed significantly across sampling stations. This was most likely due to the low fecal coliform (FC) values in the upstream compared with the midstream and downstream. The generally high FC and TC levels throughout the sampling period confirmed the presence of fecal pollution in the rivers. Organic pollution and the presence of coliforms could be related to the accumulation of wastewater due to high impact human activities across the river networks. It is therefore recommended to conduct an inventory and monitor non-point sources of water pollution, establish wastewater treatment measures and enforce policies for river protection.

The use of surface waters such as rivers for domestic, agricultural andindustrial purposes have made them vulnerable to pollution leading to impairedwater quality. The water quality of Lahug River in Cebu City was evaluated usingcoliforms as indicators, in relation with physicochemical parameters such as biological oxygen demand (BOD), conductivity, dissolved oxygen (DO), nitrate,pH, phosphate, salinity, temperature, total dissolved solids (TDS) and totalsuspended solids (TSS). Sampling was done once a month from November 2011to April 2012 in three stations covering the upstream, midstream and downstream.The multiple tube fermentation technique was used for the analysis of coliforms.The level of these indicator bacteria increased from the upstream towards thelower reaches of the river especially in the months of February to April; however,the difference in values across time was not significant. This implies that therewas a continuous fecal pollution in the river. There were no statistically significantcorrelations between FCs and TCs with the physicochemical parameters. Anegative relationship was observed among FCs and TCs with pH, TSS, DOand nitrate (p>0.05). These results suggest the presence of sewage and organicpollutants in the river.Keywords: Aquatic Ecology, water quality, coliform, physicochemical parameters,experimental design, Philippines

Coral reefs offer valuable ecosystem goods and services, such as coastal protection, erosion regulation, fishery, biodiversity, habitat and nursery grounds. However, they face threats from anthropogenic activities, including poor water quality, global warming, coastal development and unsustainable fisheries. Marine Protected Areas (MPAs) provide a structured and holistic approach in addressing these threats. Regular monitoring and assessment of these MPAs are crucial components in evaluating the MPAs design and effectiveness. Two coral reefs (i.e. Poblacion and Kadurong Reefs) were established as MPAs in Liloan, Cebu, Philippines to protect crucial habitat and biodiversity with the hope of improving fisheries by avoiding fish stock disintegration. These coral reefs provide shelter to many commercially-significant fish species, supporting subsistence and livelihood in the community. These MPAs are not only biologically rich, but they also support socio-economic stability. Hence, management and protection of the coral reefs in the MPAs of Liloan, Cebu is of paramount importance. To formulate conservation and applicable management measures, research and monitoring should be in place. This paper presents the data collected from the short term monitoring in the Poblaction and Kadurong Reefs. The paper describes an important set of data that can be used by the stakeholders to benchmark biophysical assessments for management of marine-protected areas in Liloan. This data paper provides baseline information on the health of the coral reefs of the MPAs in Liloan, Cebu. Datasets covering physico-chemical and biological parameters inclusive of water quality, coral reef cover, fish and plankton occurrence and abundance were determined using the standard protocols for surveying tropical marine resources. The results will serve as a benchmark in formulating guidelines and implementing relevant policies for the effective management and protection of the MPAs in Liloan, Cebu, Philippines.

The study aimed to provide baseline data by assessing the nutrient levels and sediment load in Buhisan, Bulacao and Lahug Rivers. Specifically