Temperature-Regulated IncX3 Plasmid Characteristics and the Role of Plasmid-Encoded H-NS in Thermoregulation

Carbapenem-resistant Enterobacteriaceae (CRE) are a critical public health problem worldwide. Globally, IncX3-type plasmids have emerged as the predominant vehicles carrying the metallo-β-lactamase gene blaNDM. Although blaNDM-bearing IncX3 plasmids have been found in various hosts from diverse environments, whether their transfer and persistence properties vary under different conditions and what factors influence any variation is unknown. By observing the effects of different temperatures on IncX3 plasmid conjugation rates, stability, and effects on host fitness in Escherichia coli, we demonstrate that temperature is an important determinant of plasmid phenotypes. The IncX3 plasmid pGZIncX3 transferred at highest frequencies, was most stable and imposed lower fitness costs at 37°C. Temperature-regulated variation in pGZIncX3 properties involved a thermoregulated plasmid-encoded H-NS-like protein, which was produced at higher levels at 30°C and 42°C and inhibited the expression of type IV secretion system genes involved in conjugation. These findings suggest that blaNDM-bearing IncX3 plasmids are adapted to carriage by enterobacteria that colonize mammalian hosts and could explain the rapid dissemination of these plasmids among human-associated species, particularly in hospital settings.

Pesticide Residue Monitoring on Agriculture in Indonesia

<p class="JSDLAbstrak"><strong>Abstra</strong><strong>ct. </strong>Most agricultural producers use pesticides to prevent pests and increase yield and quality of the food they grow. Pesticides can damage people’s health, and lead to birth defects (<em>teratogenic </em>in character) and death in humans and animals. Many of these chemical residues, especially derivatives of <em>organochlorine </em>pesticides, demonstrate dangerous bioaccumulation levels in the body and environment. The problems caused by<em> organochlorine</em> residues (<em>lindan, aldrin, dieldrin, endrin, heptachlor and DDT</em>) on agricultural lands that are still found today are generally the consequence of past usage that dates back to the1960s. Research on pesticide residues in Indonesia was carried out several years ago by various research institutes and universities and some of these results were collected between 1985 and 2017. Data distribution of the results on pesticide residues include in Aceh, North Sumatra, West Sumatra, Jambi, Bengkulu, Lampung, Banten, Jakarta, West Java, Central Java, East Java, Yogyakarta, Bali, South Kalimantan, North Sulawesi, South Sulawesi, Gorontalo, Maluku, and Papua. Most of the pesticide residue research has been conducted on vegetables. Pesticide residues were found in various commodities and matrices such as rice, soybeans, cow's milk, chicken eggs, fruit ingredients, vegetables, soil, paddy water, river water, lake water, pond water, sea water, water birds, animal feed, fish, frogs, lamb, birds, eggs, tea, and honey. Pesticide residues found were insecticide (<em>organochlorine, organophosphate, carbamate, pyrethroid</em>), and fungicide (<em>dimethomorp, fenobucarb, propineb, benomyl, carbendazim</em> and <em>thiametoxam). Organochlorine</em> insecticides have been banned, but the residues are still found today. This is due to the nature of <em>organochlorines</em> which have high persistence properties. Even though insecticide residues (<em>organophosphate, carbamate, pirethroid</em>) found in food commodities are still below the maximum residual limit (MRL), namely SNI 7313: 2008, but some close to MRL. Particularly for <em>organochlorine</em> residues in soil, water and plants insecticides must be monitored because they are persistent, toxic and accumulative. This paper aims to review of pesticide residues in various products including food, and the potential impact of pesticide residues on human health.</p><p class="JSDLAbstrak"> </p><p class="JSDLAbstrak"><strong>Abstrak. </strong>Sebagian besar produsen pertanian menggunakan pestisida untuk mencegah hama dan meningkatkan hasil dan kualitas makanan yang mereka tanam. Pestisida dapat merusak kesehatan manusia, dan bersifat <em>teratogenik</em> dan mematikan pada manusia dan hewan. Banyak dari residu kimia ini, terutama turunan pestisida <em>organoklorin</em>, menunjukkan tingkat bioakumulasi yang berbahaya dalam tubuh manusia dan lingkungan. Masalah tersebut disebabkan oleh residu <em>organoklorin</em> (<em>lindan, aldrin, dieldrin, endrin, heptachlor</em> dan <em>DDT</em>) yang digunakan sejak tahun 1960-an. Penelitian tentang residu pestisida di Indonesia dilakukan beberapa tahun yang lalu oleh berbagai lembaga penelitian dan universitas yang dikumpulkan antara tahun 1985 dan 2017. Distribusi data hasil residu pestisida tersebar di Aceh, Sumatera Utara, Sumatera Barat, Jambi, Bengkulu, Lampung, Banten, Jakarta, Jawa Barat, Jawa Tengah, Jawa Timur, Yogyakarta, Bali, Kalimantan Selatan, Sulawesi Utara dan Selatan, Gorontalo, Maluku, dan Papua. Penelitian yang telah dilakukan menemukan residu pestisida tidak hanya ditemukan di berbagai komoditas pertanian seperti beras, kedelai, susu sapi, telur ayam, bahan buah, sayuran tetapi juga pada tanah, sawah, air sungai, air danau, air kolam, air laut, burung air, pakan ternak, ikan, katak, domba, telur burung, teh, dan madu. Residu pestisida yang banyak ditemukan di lapangan adalah insektisida (<em>organoklorin, organofosfat, karbamat, piretroid</em>), dan fungisida (<em>dimethomorp, fenobucarb, propineb, benomyl, carbendazim</em> dan <em>thiametoxam</em>). Insektisida golongan <em>organoklorin </em>telah dilarang penggunaannya, namun residunya masih ditemukan hingga kini. Hal ini dikarenakan sifat organoklorin yang memiliki sifat persistensi yang tinggi. Residu insektisida (<em>organofosfat, karbamat, piretroid</em>) yang ditemukan di dalam komoditas pangan secara umum masih di bawah batas maksimum residu (BMR) yang mengacu pada standar nasional, yaitu SNI 7313: 2008, namun beberapa residu insektisida telah mendekati BMR. Khusus untuk residu insektisida golongan <em>organoklorin</em> di dalam tanah, air dan tanaman harus dipantau karena sifatnya yang persisten, beracun, dan akumulatif. Makalah ini bertujuan untuk mengkaji residu pestisida dalam berbagai produk termasuk makanan, dan dampak potensial residu pestisida pada kesehatan manusia.</p>

Stochastic Modeling for HIV and AIDS Epidemics With Viral Load Detectability

In this paper, we investigated on the stochastic epidemic model by incorporating viral load detectability. We derived HIV and AIDS stochastic model from the deterministic counterpart model and presented a stochastic threshold in terms of stochastic basic reproduction number. We showed that R_s^0 &lt; 1 then the disease dies out exponentially and when R_s^0 &gt; 1 the disease persists in the population. We further derived the existence and uniqueness, extinction and persistence properties of the stochastic model models, then the numerical simulation is done by using Milsten&rsquo;s numerical scheme. The finding shows that the random perturbation introduced in the stochastic model suppresses disease outbreak as compared to its deterministic counterparts which provide some useful control strategies to eradicate the disease

Paleo-hydrologic reconstruction of 400 years of past flows at a weekly time step for major rivers of Western Canada

The assumption of stationarity in water resources no longer holds, particularly within the context of future climate change. Plausible scenarios of flows that fluctuate outside the envelope of variability of the gauging data are required to assess the robustness of water resource systems to future conditions. This study presents a novel method of generating weekly time step flows based on tree-ring chronology data. Specifically, this method addresses two long-standing challenges with paleo-reconstruction: (i) the typically limited predictive power of tree-ring data at the annual and sub-annual scale and (ii) the inflated short-term persistence in tree-ring time series and improper use of pre-whitening. Unlike the conventional approach, this method establishes relationships between tree-ring chronologies and naturalized flow at a biennial scale to preserve persistence properties and variability of hydrological time series. Biennial flow reconstructions are further disaggregated to weekly flow reconstructions, according to the weekly flow distribution of reference 2-year instrumental periods, identified as periods with broadly similar tree-ring properties to those of every 2-year paleo-period. The Saskatchewan River basin (SaskRB) in Western Canada is selected as a study area, and weekly flows in its four major tributaries are extended back to the year 1600. The study shows that the reconstructed flows properly preserve the statistical properties of the reference flows, particularly in terms of short- to long-term persistence and the structure of variability across timescales. An ensemble approach is presented to represent the uncertainty inherent in the statistical relationships and disaggregation method. The ensemble of reconstructed weekly flows are publicly available for download from https://doi.org/10.20383/101.0139 (Slaughter and Razavi, 2019).