Haroun Chenchouni

Bacterial load of German cockroach (Blattella germanica) found in hospital environment

Abstract Background: Cockroaches are among the most common pests in public dwellings and health facilities. Their presence can raise safety concerns, especially as they maybe carriers of pathogenic organisms. Methods: This study was carried out to isolate and identify the bacterial flora from German cockroaches (Blattella germanica). Cockroaches collected by hand catches from two public hospital environments in Tebessa city (northeast Algeria) were screened for microbial load from their external surfaces and alimentary tract using standard bacterial protocols. Results: A total of 174 bacterial isolates were isolated from 39 German cockroach specimens. The most common and abundant bacterial species belonged to the Pseudomonas group (23.5%) and Serratia (13.2%). Pathogens like Staphylococcus aureus were also isolated, as well as opportunistic pathogens like Klebsiella species and food spoilage bacteria such as Enterobacter and Citrobacter species were isolated from both external surface and digestive tract of the insect. Generalized linear models (GLM) were performed to analyze the variation of abundances and occurrences of bacterial isolates harboured by B. germanica. The GLMs revealed that the main factors affecting variation of bacterial diversity and abundance were sex and hospital (P < 0.001). Conclusion: The findings of this study suggest that German cockroach acts as reservoir and potential vector of some bacterial pathogens.

Ecological status interactions for assessing bird diversity in relation to a heterogeneous landscape structure

Avian diversity is used to assess the functionality of diverse types of habitats around Salt Lake Djendli, Northeast Algeria. The landscape is stratified into five habitat types in a gradient from wetland to forested mountains. Bird species found in these habitats can be classified into four ecological groups with decreasing degrees of aquatic specialisation and increasing forest specialisation. For each surveyed species, five ecological status were assigned. Overall, there was lower species richness in urban areas compared to other “natural” habitats. Birds have a biogeographical affinity to the western Palaearctic according to the dominant faunal types. Interactions of ecological status with phenological traits reveal that water birds are different from non-aquatic species because most of them are migrants. Moreover, overall, there is no worrying conservation status for surveyed birds. Bird diet is dependent on the ecological status that differentiate bird groups from each other due to differences in the food resources of the habitats they frequent. Phenological categories tend to link together birds of urban and open-lands. These two groups are affected by seasonal human activities. Our findings emphasise the importance of using combinations within the birds’ ecological status, which would give information on the actual state of avifauna. This approach is relevant for future programmes and conservation actions.

Floristic composition and analysis of spontaneous vegetation of Sabkha Djendli in north-east Algeria

We conducted a phyto-ecological analysis of the Sebkha Djendli located in the semi-arid lands of the north-eastern Algeria in order to contribute in the understanding of flora composition, diversity and factors controlling plant zonation. Eight plots, distributed on the cardinal and intercardinal points of the site, were sampled. A floristic analysis (species richness, life forms, spatial occurrence, plant cover rate and similarity) and an assessment of the effect of soil salinity and pH on the cover of dominant halophytes were performed. The results of the floristic approach showed the presence of 51 species belonging to 21 families and 45 genera. The most frequent biological types were therophytes (58%) followed by chamaephytes (18%). Vegetation cover rate ranged from 50% to 95%. The distribution of vegetation all around the edges of the Sabkha revealed the dominance of halophytic species belonging to the family Chenopodiaceae. The variation of total halophytic vegetation cover over all sampled plots seems to be affected neither by the distance from waterbody nor by plot orientation nor by the electrical conductivity and pH of soil.

Diversity assessment of vertebrate fauna in a wetland of hot hyperarid lands

A great paradox arises when we talk about biodiversity in wetlands located at hot-hyperarid lands. Ayata Lake (155 ha) belongs to the complex of wetlands of Oued Righ Valley in Algerian Lower-Sahara. Surveys conducted between October 2009 and June 2010 has allowed assessing vertebrate diversity living in the lake and its surrounding areas. Several methods and techniques were used for sampling and censing each group of vertebrate (fish, amphibians, reptiles, birds and mammals). Inventories revealed the existence of 03 fish, 02 amphibians, 06 reptiles, 55 birds, and 07 mammals. Phenological types (winter or summer migrant, resident-breeder occasional visitor) were attributed to birds then population dynamics were discussed. Birds used generally the waterbody in winter where migrants, mainly waterbirds, were abundant. We investigated for most inventoried species the specific habitats where they are occurring, and which respond to their behavioural and diet ecology. Biogeography status of vertebrate species revealed a desert affinity, which is represented mainly by Saharan and Saharo-sindian bio-models; except for birds which revealed dominance of Palaearctic biogeographical categories. This approach helped to highlight the biological resources of Ayata Lake and determine its actual ecological value. Furthermore, this study proposes some suggestions for management and conservation purposes.

Modeling the effects of climate on date palm scale (Parlatoria blanchardi) population dynamics during different phenological stages of life history under hot arid conditions

The date palm scale (DPS) Parlatoria blanchardi is a serious pest due to the damage it inflicts on its host tree (Phoenix dactylifera). To develop an effective control against DPS in arid regions, it is essential to know its bio-ecology including population dynamics and climatic factors influencing the duration and timing of life history and also the densities of different phenological stages (crawlers, first and second instars nymphs, adult males, and adult females). Monitoring of biological cycle and population dynamics of the pest were achieved through weekly counts of DPS densities on leaflets sampled at different position of date palm trees in an oasis of Ouargla region (Algerian Sahara Desert). Within this hyper-arid region, DPS established four generations per year, the most important was the spring generation. Two overlapping generations occurred in spring–early summer and two in autumn–early winter; these two pairs of generations were interspersed by two phases of high-mortality rates, the first corresponds to winter cold and the second refers to the extreme heat of summer. Statistical analysis of the effects of the studied climatic conditions (minimum, maximum and mean temperatures, precipitation, humidity, wind, rain days, and climatic indices) on the DPS densities at different phenological stages showed great variability from one stage to another. Among these, adult females were the most affected by climate factors. For the total DPS population, high values of minimum temperatures negatively affected population density, while high maximum temperatures, hygrometry, and De Martonne aridity index showed a positive influence.

Growth, physiology and yield of durum wheat (Triticum durum) treated with sewage sludge under water stress conditions

In arid and semi-arid areas, low soil fertility and water deficit considerably limit crop production. The use of sewage sludge as an organic amendment could contribute to the improvement of soil fertility and hence the agronomic production. The study aims to highlight the behaviour of durum wheat to the application of sewage sludge associated with water stress. The assessment focused on morphophysiological parameters of the wheat plant and yield. Under greenhouse conditions, the variety Mohamed Ben Bachir was treated by four water stress levels (100 %, 80 %, 50 % and 30 %). Each stress level comprised five fertilizer treatments: 20, 50 and 100 t/ha of dry sludge, 35 kg/ha of urea, and a control with no fertilization. Results revealed a significant loss in water content and chlorophyll a in leaves. Water stress negatively affected the development of wheat plants by reducing significantly seed yield, leaf area and biomass produced. Plant’s responses to water stress manifested by an accumulation of proline and a decrease in total phosphorus. However, the increasing doses of sewage sludge limited the effect of water stress. Our findings showed an increase in the amount of chlorophyll pigments, leaf area, total phosphorus, biomass and yield. In addition, excessive accumulation of proline (1.11 ± 1.03 µg/g DM) was recorded as a result of the high concentration of sludge (100 t/ha DM). The application of sewage sludge is beneficial for the wheat crop, but the high accumulation of proline in plants treated with high dose of sludge suggests to properly consider this fact. The application of sludge should be used with caution in soils where water is limited. Because the combined effect of these two factors could result in a fatal osmotic stress to crop development.

Antimicrobial Activity of Xerophytic Plant (Cotula cinerea Delile) Extracts Against Some Pathogenic Bacteria and Fungi

In the present investigation, an Algerian commonly available plant namely Cotula cinerea, found throughout sandy desert grounds, was screening for antimicrobial activity against five different human pathogenic microbes namely, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli and Candida albicans. The antimicrobial activity was evaluated using the agar disc diffusion method. Aerial parts of C. cinerea were subjected to extraction using four solvents of different polarity (70% ethanol, n-butanol, ethyl acetate and petroleum ether). Petroleum ether and n-butanol extracts had the most effective antimicrobial activity with Gram-negative K. pneumoniae demonstrating the highest susceptibility. Linear regression analysis was performed to find correlations between extract concentrations and inhibition activity. Results showed a significant increase in mean diameter of inhibition zone with increasing extract concentrations of all solvents except n-butanol. Two-way ANOVA test was used to compare the effect of C. cinerea extracts on the antimicrobial properties. All plant extracts have shown significant differences in their actions as antimicrobial agents. Indeed, the n-butanol extract at a low concentration of 0.25 mg mL -1 indicated a potent antimicrobial

Using self-organizing maps to investigate environmental factors regulating colony size and breeding success of the White Stork (Ciconia ciconia)

AbstractWe studied variations in the size of breeding colonies and in breeding performance of White Storks Ciconia ciconia in 2006–2008 in north-east Algeria. Each colony site was characterized using 12 environmental variables describing the physical environment, land-cover categories, and human activities, and by three demographic parameters: the number of breeding pairs, the number of pairs with chicks, and the number of fledged chicks per pair. Generalized linear mixed models and the self-organizing map algorithm (SOM, neural network) were used to investigate effects of biotic, abiotic, and anthropogenic factors on demographic parameters and on their relationships. Numbers of breeding pairs and of pairs with chicks were affected by the same environmental factors, mainly anthropogenic, which differed from those affecting the number of fledged chicks per pair. Numbers of fledged chicks per pair was not affected by colony size or by the number of nests with chicks. The categorization of the environmental variables into natural and anthropogenic, in connection with demographic parameters, was relevant to detect factors explaining variation in colony size and breeding parameters. The SOM proved a relevant tool to help determine actual dynamics in White Stork colonies, and thus to support effective conservation decisions at a regional scale.ZusammenfassungWelche Umweltfaktoren regulieren Koloniegröße und Bruterfolg beim WeißstorchCiconiaciconia?—der Einsatz von Selbstorganisierenden Karten Untersucht wurden Unterschiede in Brutkoloniestärke und Bruterfolg bei Weißstörchen Ciconia ciconia in Nordostalgerien, in den Jahren von 2006–2008. Jede Kolonie wurde anhand von zwölf Umweltvariablen charakterisiert, welche Auskunft über physische Umweltbedingungen, Landbedeckung und menschlichen Einfluss gaben, sowie anhand von drei demografischen Parametern: der Anzahl der Brutpaare, der Anzahl von Paaren mit Küken und der Anzahl flügger Junge pro Paar. Es wurden Generalisierte Lineare Gemischte Modelle und der Selbstorganisierende Karten-Algorithmus (Self-Organising Map, SOM, ein neuronales Netz) angewendet, um die Wirkung biotischer, abiotischer und anthropogener Faktoren auf die demografischen Parameter und die Beziehungen zwischen diesen zu untersuchen. Die Anzahl der Brutpaare und die der Paare mit Küken wurden von denselben (hauptsächlich anthropogenen) Umweltfaktoren beeinflusst. Dagegen wurde die Anzahl flügger Küken pro Paar von anderen Faktoren bestimmt: Weder die Koloniegröße noch die Anzahl von Nestern mit Küken hatten hier einen Einfluss. Die Einteilung der Umweltvariablen in natürliche und anthropogen bedingte half in Verbindung mit demografischen Parametern dabei, die Faktoren zu identifizieren, welche die Variation in Koloniegröße und den Brutparametern erklären. Die SOM-Methode erwies sich als geeignetes Werkzeug zur Beschreibung der tatsächlichen Dynamik in Weißstorch-Kolonien und stellt somit eine Hilfe bei der Festlegung effektiver Schutzmaßnahmen auf regionaler Ebene dar.

Edaphic factors controlling the distribution of inland halophytes in an ephemeral salt lake “Sabkha ecosystem” at North African semi-arid lands

This study aims to characterize soil properties and to investigate how these parameters, including soil salinity, are related to zonation and distributional patterns of halophytic plants occurring at edges of the Djendli Sabkha (northeastern Algeria). Soil samples were collected from four stations at Sabkha edges with seven samples for each station. Physicochemical soil parameters were analysed in each vegetation belt of halophytes. Relationships between soil traits were tested to determine spatial variation and their effects on vegetation cover of the principal halophyte species. The influence of pedological factors on the distribution and establishment of halophytes was considered using a redundancy analysis (RDA) and generalized linear models. Positive correlations were found between organic matter, carbon and nitrogen which were negatively correlated with electrical conductivity (EC), pH, gypsum, Na+ and Cl- concentrations. Sharp limits were found between halophyte communities even though there is a gradual change in the physicochemical environment along the gradient centre-to-edge of the Sabkha. RDA showed that edaphic variables that best explained the data were EC, pH, organic matter (OM), carbon and nitrogen contents, Na+ and Cl- concentrations. Sarcocornia fruticosa grew under higher soil salinity (EC=7.2-13.8dS/m) compared to Suaeda fruticosa and Suaeda vermiculata that afford moderate soil salinity, than Atriplex halimus established in soils with low EC values (5.5-7.3dS/m) but with high values of OM, carbon and nitrogen contents and low values of Na+, Cl- and pH. Sarcocornia fruticosa grew in soils characterized with high pH, Na+, Cl- values but relatively low in OM, carbon and nitrogen contents.

Modeling seasonal and spatial contamination of surface waters and upper sediments with trace metal elements across industrialized urban areas of the Seybouse watershed in North Africa

Industrialization and urbanization are the main sources of pollutions worldwide and particularly in developing countries. This study aims the determination of anthropogenic inputs with trace metals in aquatic ecosystems at the Plain of Annaba (NE Algeria), which is known as one of the largest industrial areas in Africa. Samples of surface waters and upper sediments were conducted in six stations: four in Meboudja wadi and two in Seybouse wadi. Contents of iron, copper, chromium, nickel, zinc, and manganese were measured by atomic absorption spectrophotometry, whereas Cd and Pb were determined using electrothermal atomic absorption spectrometry. Measurements of Hg were carried out using atomic fluorescence. Spatiotemporal variations of metal concentrations were tested using generalized linear models (GLM), whereas the influence of water pollution on sediment contamination was tested with generalized additive models (GAMs). Metal contents measured in surface water and sediments varied differently from upstream to downstream of the study wadis and between seasons. The results showed that the surface water was polluted with high levels of iron, nickel, chromium, lead, and cadmium. Values of the contamination index revealed that the surface sediments were contaminated by iron, chromium, lead, and cadmium. The GAMs indicated that water-phase metal concentrations had no significant effects on trace metal concentrations in the sediment. This suggests that seasonal metal concentrations in water phase, which are measured during the study period (2012) and are time-dependent, contribute increasingly and gradually over time—not immediately—to the accumulation of metals into the sediments. Therefore, the long-term accumulation of metals in the sediments resulted from the continuous discharges of metals in the water phase. The anthropogenic impacts are marked by high contaminations of Meboudja wadi particularly in downstream areas of the steel factory and the nearby industrial areas. The direct industrial discharges into the water and atmosphere (iron, lead, cadmium) as well as urban disposals and agricultural activities are at the origin of these contaminations.